Corals of Andamanand how to tell them apart

How to identify it

• A wide, flat, thin table with a fine, lacy top.
• Short branchlets point upwards.
• The cup at the tip of each branchlet sticks out above the rest.
• Tentacles are often out during the day.

Where to see it in the Andamans

Upper reef slopes, drop-offs and lagoons, at about 3-25 m. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep), and at seven other islands. It also appears in a 2018-19 CMFRI photo survey of reefs at Havelock, Neil, North Bay and Wandoor, though that paper pools the four sites and calls its IDs tentative.

How it lives

The tiny algae inside it make food from sunlight and pass most of it to the coral. It also catches tiny drifting animals with its tentacles.

Easy to confuse with

• Brush Coral: The cup at each branchlet tip does not stick out, and the side cups form small rosettes.

How to identify it

• A low clump of thick fingers, usually under 20 cm long.
• Each finger tapers to a large, dome-shaped cup at the tip.
• Small side branches or extra tip cups at the base of the fingers.
• Side cups of two sizes, the bigger ones in rows.

Where to see it in the Andamans

Reef flats, reef tops and upper reef slopes open to the waves, at about 3-10 m. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep), and at seven other islands.

How it lives

Each finger is covered in tiny polyps, the small animals that build the coral. Most of their food comes from algae living in their tissue. The polyps also catch tiny drifting animals, mostly at night.

Easy to confuse with

• Digitate Acropora: Much thinner fingers, often rising from a flat plate.
• Acropora gemmifera: The tip cup is smaller, and the side cups get longer towards the base of each finger.

How to identify it

• Tree-like colonies of round branches, like antlers.
• Forms thickets.
• Short, compact branches in shallow water; longer, more open branches deeper down.
• The cup at each branch tip sticks out; the side cups are small tubes.
• Branch ends are usually paler.

Where to see it in the Andamans

Reef slopes and lagoons. Under its old name it was named as one of the main Acropora corals in a 2010 bleaching survey of seven Andaman reef sites, two of them at Havelock (the Aquarium and Wall dive sites); the paper does not say which sites each coral grew at. The 2018-19 CMFRI photo survey listed it too (Havelock, Neil, North Bay and Wandoor pooled, IDs tentative).

How it lives

It gets most of its food from tiny algae living inside it, and catches tiny drifting animals with its tentacles, mostly at night. The branches are short and compact in shallow water and grow longer and more open deeper down.

Heat, bleaching and threats

Very sensitive to heat. In April and May 2010 the sea around the Andamans stayed above 31°C for a long time, and branching Acropora corals were the worst hit. Large Acropora beds at South Button were almost 100% bleached.

Easy to confuse with

• Acropora intermedia: Another staghorn. Its side cups look rough, like a file.
• Acropora cervicornis: Looks the same, but lives only in the Caribbean and western Atlantic, not in the Andamans.

How to identify it

• Thick, crust-like plates with upright ridges, columns or blades.
• Tall and upright in calm water; low and uneven where waves are strong.
• Usually no bigger cup at the branch tip (Acropora has one).
• Cups are smooth, rounded and stick out a little.
• Pale cream or brown.

Where to see it in the Andamans

Found in all kinds of reef, at about 2-20 m, and can take over wave-washed parts of the reef. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep), and at five other islands (under its old name, Acropora palifera).

How it lives

The shape of each colony follows the waves. In calm water it grows tall ridges and columns. On reef beaten by waves it stays low and lumpy.

Easy to confuse with

• Isopora cuneata: Smaller, flatter branches and finer, rounder cups. Hard to tell apart unless both grow side by side.

How to identify it

• Flat crusts or low, lumpy colonies.
• Surface covered in small bumps, each about as wide as one cup.
• Tiny cups, some raised, some sunk into the surface.
• Blue colonies may look pink or purple in photos.

Where to see it in the Andamans

Most kinds of reef, from the surface down to about 52 m. Recorded at Havelock (Swaraj Dweep), Nicolson and Inglis islands in a ZSI survey of Ritchie's Archipelago. A CMFRI photo survey in 2018-19 also lists it for the Havelock, Neil, North Bay and Wandoor reefs, with the sites pooled and the IDs marked tentative.

How it lives

There is one polyp in each tiny cup: a small animal with a ring of tentacles. The algae in its tissue supply most of its food, and at night the polyps also catch tiny drifting animals.

Easy to confuse with

• Montipora monasteriata: Has larger bumps between the cups.
• Montipora aequituberculata: Grows as thin, overlapping plates or whorls, not lumps.

How to identify it

• Wide, flat plates or tables, or tiers of small plates.
• Held up on a central stalk.
• Fine branchlets all point up to the same height.
• Side cups form tiny rosettes.
• Blue edges may look pink in photos.

Where to see it in the Andamans

Upper reef slopes and outer reef flats, most common in shallow to middle depths. Of the 11 islands in a ZSI survey of Ritchie's Archipelago, it was found on eight, Havelock (Swaraj Dweep) and Neil (Shaheed Dweep) among them.

How it lives

A table is one colony: thousands of tiny polyps joined by a thin living skin over a stony skeleton. Big tables are long-lived.

Heat, bleaching and threats

One of the corals that bleaches most easily. In Palau its death rate after bleaching was estimated at close to 100%.

Easy to confuse with

• Tabling Acropora: The cup at each branchlet tip sticks out, and the side cups do not form rosettes.

How to identify it

• Short, small fingers rising from a flat plate.
• Fingers round or slightly tapered, sometimes with side branches.
• Side cups are small tubes, all the same size, with slightly flared lips.
• Branch tips are often pale blue, cream or yellow.

Where to see it in the Andamans

Wave-washed back edges of reefs and reef flats between the tides, from the surface to about 12 m. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep).

How it lives

Tiny algae living inside the coral make most of its food from sunlight. Its genes suggest it may need them for more than food: it seems to lack an enzyme needed to make cysteine, one of the building blocks of protein, so it may get cysteine from its algae.

Easy to confuse with

• Finger Coral: Much thicker, larger fingers.
• Acropora monticulosa: Much larger, cone-shaped branches.

How to identify it

• Upright fingers or small tree shapes.
• Branches sometimes fuse together.
• Smooth surface with tiny cups sunk into it.
• No cup sticking out at the branch tip.

Where to see it in the Andamans

Shallow reefs, from the surface to about 33 m. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep), and at Nicolson and Outram islands. It has also been photographed near Sunrise Island at Sri Vijaya Puram (Port Blair) and at other spots in South Andaman.

How it lives

Its polyps sit in tiny cups sunk into the smooth surface. Food comes mostly from the algae in its tissue, plus tiny drifting animals caught at night.

Easy to confuse with

• Yellow Finger Coral: ZSI notes the two are often confused in the Andamans. Porites has tiny pitted cups, and its polyps are often out by day.
• Staghorn Coral and other Acropora: Acropora branches end in a cup that sticks out. Montipora branches are smooth.
• Montipora samarensis: A very similar branching Montipora; needs a close look.

How to identify it

• Low, rounded cushions or clumps.
• Short branchlets, all about the same height.
• Side cups all the same size, with rounded, flared lower lips.
• Side cups form rosettes near the branchlet tips.
• Usually brown or muddy green.

Where to see it in the Andamans

Mostly on reef flats, also in lagoons and on upper reef slopes. Recorded at Havelock (Swaraj Dweep) and five other islands in a ZSI survey of Ritchie's Archipelago.

How it lives

Like other Acropora, it lives mostly on food made by the algae in its tissue. Its tentacles also catch tiny drifting animals, mostly after dark.

Easy to confuse with

• Acropora spathulata: Clumps with thicker branchlets.

How to identify it

• Compact, bushy clump of short, uneven branches.
• Small bumps that merge into the branches, with no clear line between bump and branch.
• Thick, sturdy branches where waves are strong; thin and open in calm or deeper water.
• Pale brown, pink or greenish.

Where to see it in the Andamans

Almost any shallow place, from reef fronts beaten by waves to mangroves and jetty pillars, usually at 1-15 m. In the Andamans it grows mostly on reef flats. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and all the other islands.

How it lives

Its polyps usually come out only at night. Most of its food comes from the algae in its tissue.

Heat, bleaching and threats

Corals of its family bleach very easily. After the 1998 heat wave in Okinawa, Japan, they were among the worst hit, together with branching Acropora.

Easy to confuse with

• Pocillopora acuta: Finer branches with pointed ends. Only a DNA test can tell them apart for sure.
• Cauliflower Coral: Upright branches with clear, separate bumps, which give a rough, ragged look.
• Bird's Nest Coral: Thin, needle-like branches with no bumps.

How to identify it

• Rounded clump of thick, upright branches.
• Clear bumps of uneven size on the branches, which give a rough, ragged look.
• Thick and compact on reefs beaten by waves, thinner and more open in calm water.
• Seldom more than 50 cm across.

Where to see it in the Andamans

Most shallow habitats, from exposed reef fronts to sheltered reefs near the shore. In the Andamans it often grows mixed with Hood Coral and Lace Coral. It turned up at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and eight other islands in the Zoological Survey of India's survey of Ritchie's Archipelago.

How it lives

Its polyps usually come out only at night. Small crabs live between its branches and help protect it.

Easy to confuse with

• Lace Coral: The bumps merge into the branches, with no clear line between them.
• Hood Coral: Smooth, blunt branches with no bumps.
• Pocillopora meandrina: Shorter, flatter branches with smaller bumps.

How to identify it

• Smooth, rounded columns or clubs, like thumbs or shoulder blades.
• Columns divide but never join back together.
• Can also grow as flat plates.
• Small, thick-walled cups, with ridges of two different sizes running out from each.
• Plain pale grey, cream or dull brown.

Where to see it in the Andamans

Places with strong waves or currents, from shallow reef to deep slopes. The Zoological Survey of India and older coral checklists list it for the Andaman and Nicobar Islands, but we found no published survey that names a site for it here.

How it lives

In most Pavona corals the polyps come out only at night, so by day the columns look smooth and bare.

Heat, bleaching and threats

In Palau it was recorded with a high level of bleaching and a high death rate.

Easy to confuse with

• Pavona duerdeni: Same kind of cups, but grows as dense mounds, not clubs.
• Pavona bipartita: Looks like the flat-plate form. Check for columns nearby.
• Column-shaped Porites: Porites cups are tiny (under 2 mm), and the surface looks finely pitted.

How to identify it

• Thin, frilly plates in whorls or tiers, like lettuce.
• Small, well-spaced cups (2.5-4 mm) on the top side, often darker than the plate.
• Surface looks slightly rough or spiny close up.
• In the Andamans greyish green, sometimes with a pink edge.

Where to see it in the Andamans

Shallow reefs with flat bottoms, at about 3-35 m. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Wilson and Sir William Peel islands.

How it lives

Its polyps come out only at night. By day you see the plates and their small, darker cups.

Heat, bleaching and threats

In the May 2010 bleaching, it was the main fully bleached coral at North Bay, near Sri Vijaya Puram (Port Blair).

Easy to confuse with

• Merulina Coral: Its plates carry short ridges and valleys that fan out from the centre, not separate round cups.
• Echinopora gemmacea: Plates, crusts or lumps, sometimes with twisted branches, and slightly bigger cups (3.5-4.5 mm).

How to identify it

• Separate tube-shaped cups with sharp, star-like ridges.
• Cups of mixed sizes, usually under 10 mm wide.
• Tentacles out in the day, often with white tips; they can hide the skeleton.
• Small colonies are cushions or low domes; big ones become mounds or columns.

Where to see it in the Andamans

Reefs sheltered from strong waves. In the Andamans it grows on reef flats, in crevices and on muddy bottoms. Recorded at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and eight other islands in a ZSI survey of Ritchie's Archipelago.

How it lives

It has tiny algae living in its tissue, which make food from sunlight. It also catches small prey with its tentacles.

Easy to confuse with

• Galaxea astreata: Smaller cups (3-4.5 mm), and its tentacles are seldom fully out in the day.

How to identify it

• Surface covered in small cones (5-8 mm).
• Crust, lumpy mound or short branches, sometimes all three in one colony.
• Long, shaggy tentacles of the same length, often out by day, make it look furry.
• Cream or dull green.

Where to see it in the Andamans

All kinds of reef, especially lagoons and sheltered slopes. In the Andamans it grows on wave-washed reef flats. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep), Nicolson, Wilson, Outram and Sir William Peel islands.

How it lives

Unlike most horn corals, its tentacles are often out by day as well as at night. The tentacles grow in a ring around the base of each cone.

Easy to confuse with

• Branching Horn Coral: Upright, often flattened branches, usually with no crust at the base, and tentacles mostly out only at night.
• Hydnophora microconos: A rounded mound with smaller cones.
• Hydnophora pilosa: Dark brown polyps with white-tipped tentacles.

How to identify it

• Bushy clump of thin branches tapering to sharp, needle-like tips.
• Branches often fuse together.
• Tiny cups in neat rows along the branches.
• Usually pink elsewhere; Andaman colonies are cream to pale brown.

Where to see it in the Andamans

Shallow reefs, from reef flats between the tides to about 20 m; thickets are mostly at 6-20 m. In the Andamans it grows mostly on soft, muddy bottoms. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and eight other islands.

How it lives

Its polyps stay in during the day and come out at night. Small crabs and other animals live among its branches.

Heat, bleaching and threats

Corals of its family bleach easily. The IUCN rated it Least Concern in 2008 and Vulnerable in 2023.

Easy to confuse with

• Hood Coral: Thick branches with blunt tips.
• Lace Coral: Branches covered in bumps, not smooth needles.
• Seriatopora caliendrum: Thicker branches that do not taper to a point.

How to identify it

• Short, thick branches with blunt, rounded tips.
• Big colonies become lumpy and almost solid.
• Smooth surface with no bumps.
• Each tiny cup has a small hood over it (needs a close look).
• Pink to brownish pink in the Andamans.

Where to see it in the Andamans

Shallow reefs open to the waves, from the reef flat to middle depths. In the Andamans it is common on shallow reef slopes. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Wilson and Henry Lawrence islands.

How it lives

Colonies stay small, up to about 50 cm across, and live mostly on food made by the algae in their tissue.

Heat, bleaching and threats

Prone to bleaching. It is listed as Near Threatened on the IUCN Red List.

Easy to confuse with

• Cauliflower Coral: Branches covered in bumps. Hood Coral is smooth.
• Bird's Nest Coral: Thin branches tapering to needle points.
• Stylophora danae: Very similar; needs a close look at the cups.

How to identify it

• Thick, finger-like branches, round in section.
• Often rises from a crusty base.
• Smooth surface: the cups are tiny and shallow.
• Cream, yellow, blue or green.

Where to see it in the Andamans

Lagoons, back edges of reefs and shallow reef flats. ZSI's island-by-island survey of Ritchie's Archipelago lists it for Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and seven other islands.

How it lives

Each tiny cup holds one polyp, a small animal with a ring of tentacles. The cups are packed edge to edge.

Easy to confuse with

• Finger Montipora: ZSI notes the two are often confused in the Andamans. Montipora has tiny sunken cups spaced apart; Porites cups are packed edge to edge.
• Porites attenuata or Porites compressa: Flatter or more uneven branches; needs a close look.
• Palauastrea ramosa: Easy to confuse underwater. Check the cups up close.

How to identify it

• Flat plates, often with short branches in the same colony.
• Short, straight ridges and valleys fan out from the centre and then split.
• Flat parts often show rings of growth lines.
• Pale blue or pale brown.

Where to see it in the Andamans

Many kinds of reef, especially lagoons, from shallow to middle depths. In the Andamans it grows inside crevices and on steep, overhanging rocks. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and six other islands.

How it lives

Its tentacles usually come out only at night. The rings of growth lines on the flat parts show how the plate has spread outwards.

Easy to confuse with

• Hedgehog Coral: Its plates carry separate round cups, not fan-shaped ridges.
• Merulina scabricula: Very similar; usually more branching, and mostly on outer slopes.

How to identify it

• Bushy colony of uneven, often slightly flattened branches.
• Usually no crusty base.
• Branches 7-12 mm thick.
• Small cones all over the branches, often joining into ridges down the sides.
• Cream or green.

Where to see it in the Andamans

Shallow reefs, especially lagoons and sheltered slopes. In the Andamans it grows on calm upper slopes. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), John Lawrence and Sir William Peel islands.

How it lives

Its polyps usually stay in until night, which leaves the little cones easy to see in daylight.

Easy to confuse with

• Encrusting Horn Coral: Grows as crusts, mounds or stubby branches, and its long, shaggy tentacles are often out by day.

How to identify it

• A rounded or flat boulder covered in long, winding valleys and ridges.
• In most species the valleys run on in long lines; a few (P. pini, P. verweyi) have short valleys or some single cups.
• Often brown walls with grey or green valleys.
• Valleys about 3-10 mm wide, depending on the species.

Where to see it in the Andamans

Most kinds of reef, from reef flats to about 30-40 m. In the Andamans it grows on wave-washed reef edges, outer reef slopes, shallow reef flats and the back edges of reefs. Recorded at Havelock (Swaraj Dweep) and Neil (Shaheed Dweep) in a ZSI survey of Ritchie's Archipelago, where one species, Platygyra lamellina, was found at 10 of the 11 islands checked.

How it lives

The polyps, the small animals that build the coral, come out only at night. One species, Platygyra sinensis, grows about 6-12 mm a year.

Easy to confuse with

• Least Valley Coral: Much narrower, very even valleys, only about 3 mm wide.
• Goniastrea: Looks alike underwater, but usually has a clear crown of small lobes inside each centre.
• Radiating Brain Coral: Much wider, fleshy valleys (about 20-25 mm) with a groove along the wall tops.

How to identify it

• Small, low lumps or crusts.
• Cups share their walls; some join into short valleys, usually with fewer than four centres.
• Thick walls, with a neat crown of small lobes inside each cup.
• Usually pale brown or pink.

Where to see it in the Andamans

Most shallow reef areas, from the surface to about 40 m. In the Andamans it grows on shallow reefs, fixed at the mouths of crevices. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep).

How it lives

Tiny algae in its tissue make food from sunlight and share it with the coral.

Easy to confuse with

• Goniastrea edwardsi: Much smaller cups.
• Goniastrea retiformis: Small, neat cups with 4-6 sides and thin walls; colonies often over 1 m.
• Larger Star Coral: No crown of lobes inside the cups, and teeth stick up above the walls.

How to identify it

• A flat, thin crust on rock.
• Angular cups that share their walls.
• Thin plates inside each cup slope steeply down to the centre.
• Grey, green or yellow, often with darker sides.

Where to see it in the Andamans

A wide range of reef areas, usually at about 1-20 m. Recorded at Neil (Shaheed Dweep), and at no other island, in a ZSI survey of Ritchie's Archipelago.

How it lives

In this genus the polyps usually stay in until night, so in daylight there is only the crust of cups to see.

Easy to confuse with

• Leptastrea purpurea: Thin plates packed tightly in each cup, and cups of different sizes in one colony.
• Leptastrea bottae: Round cups with a fine groove between them; white or cream with darker centres.
• Cyphastrea: Small, round cups raised one by one, not sharing walls.

How to identify it

• Small crusts or low mounds, up to about 16 cm across.
• Cups with straight sides that share their walls, 3-6 mm across.
• Thin plates inside the cups join in fan-like groups, with fine saw-like teeth.
• Pale grey with white walls (plain brown in the western Indian Ocean).

Where to see it in the Andamans

Very shallow water, attached to bare rock, down to about 20 m. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), South Button and Sir Hugh Rose islands.

How it lives

It stays small and spreads as a thin layer over rock.

Easy to confuse with

• Siderastrea savignyana: Smaller cups (2-4 mm), colonies up to 1 m, and no saw-like teeth.
• Crust Coral: Looks similar at first glance, but its cups are larger, about 5-9 mm.

How to identify it

• A big, smooth dome or helmet-shaped boulder.
• The surface looks smooth; each cup is only about 1 mm wide.
• In very shallow water it can grow as a "micro-atoll": a flat dead top with living sides.
• Usually cream or yellow.

Where to see it in the Andamans

From reef flats between the tides to about 50 m, on back reefs, lagoons and fringing reefs. In the Andamans it grows mostly with Porites lobata and Porites solida on outer reef slopes. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Sir William Peel and Inglis islands.

How it lives

Colonies grow about 1-2 cm a year. The algae in its tissue supply most of its food.

Heat, bleaching and threats

In the May 2010 bleaching, massive Porites corals were fully bleached at some Andaman sites, though boulder corals bleached less overall than branching corals.

Easy to confuse with

• Porites lobata: Cups look more open, and the surface is often lumpy. Very hard to tell apart underwater.
• Honeycomb Coral: Much bigger cups (7-9 mm), each a low cone with a small mouth.

How to identify it

• A smooth, even dome, like a giant honeycomb.
• Each cup is a low cone with a small opening.
• Very thick walls between the cups, which are about 7-9 mm wide.
• Usually plain cream or grey.

Where to see it in the Andamans

Both exposed and sheltered reefs, from the surface to about 30 m. A Zoological Survey of India survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Outram, South Button, Sir Hugh Rose and John Lawrence islands. A 2010 bleaching survey also recorded it at the Wall dive site off Havelock.

How it lives

Its tentacles come out only at night. It grows very slowly, about 2-3 mm a year in colonies measured in the Red Sea.

Heat, bleaching and threats

During the mass bleaching of May 2010, this coral was extensively bleached at the Wall dive site off Havelock.

Easy to confuse with

• Knob Coral: Cups are not raised as low cones with small mouths, and the walls are thinner.
• Hump Coral: Cups are tiny (about 1 mm), so the surface looks smooth, not like a honeycomb.

How to identify it

• A rounded boulder with an even surface.
• Very narrow, winding valleys, only about 3 mm wide.
• Valleys all the same width across the colony.
• Walls and valleys often in different colours: cream, brown or green.

Where to see it in the Andamans

Upper reef slopes and shallow reef flats, from the surface to about 30 m. On ZSI's list for Ritchie's Archipelago it appears at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Nicolson, Inglis and South Button islands.

How it lives

Its polyps come out only at night, so by day only the walls and valleys show.

Easy to confuse with

• Greater Maze Coral: Wider, less even valleys.
• Leptoria irregularis: Wider valleys that run straight at the edge of the colony.

How to identify it

• A rounded or lumpy boulder, sometimes over 1 m across.
• Cups share their walls, with no gap between them.
• Round cups with thick walls, 7.5-15 mm wide.
• Teeth on the thin inner plates stick up above the walls.
• Pale brown with brown or green centres.

Where to see it in the Andamans

Most kinds of reef, usually at 1-20 m and recorded down to 50 m. A ZSI survey of Ritchie's Archipelago recorded it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and seven other islands (9 of the 11 checked).

How it lives

Polyps in this genus stay hidden until night. In daylight, look for the thick walls the cups share.

Easy to confuse with

• Favites halicora: Thicker walls, and the cups tend to pull apart; plain yellowish or greenish brown. Also recorded at Havelock and Neil.
• Knob Coral: Each cup has its own wall, with a gap between neighbours.
• Lesser Star Coral: A neat crown of small lobes inside each cup.

How to identify it

• A rounded boulder.
• Round cups, each with its own wall, 7-10 mm wide.
• Cups packed close in shallow water, more spaced out deeper down.
• Pale yellow, cream or green, with dark centres.

Where to see it in the Andamans

All kinds of reef, from the surface to about 50 m, often common on the back edges of reefs. In the Andamans it grows on reef flats and sheltered reef shelves. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and every other island except John Lawrence.

How it lives

Colonies measured on Pacific reefs grew about 3-6 mm a year. Most of its food comes from the algae in its tissue.

Easy to confuse with

• Dipsastraea favus: Cone-shaped cups, often in mixed colours with pale centres.
• Dipsastraea speciosa: More cone-shaped cups with finer, more numerous inner plates, and seldom dark centres.
• Larger Star Coral: Cups share their walls, with no gap between them.

How to identify it

• A flat or domed colony of big, fleshy lobes or short winding valleys.
• Very large cups, about 1.5-2.7 cm wide.
• Soft, fleshy tissue hides the skeleton.
• Colours often in rings around the mouths. Greenish brown in the Andamans.

Where to see it in the Andamans

Upper reef slopes, at about 1-50 m, where it can be the main coral and form big stands of one species. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and seven other islands (9 of the 11 checked).

How it lives

Each big lobe is covered in thick, fleshy tissue that hides the stony skeleton.

Heat, bleaching and threats

The IUCN listed it as Endangered in 2022, because its numbers are expected to fall steeply in future.

Easy to confuse with

• Radiating Brain Coral: Long, joined valleys with a groove along the wall tops, not separate lobes.
• Lobophyllia robusta: Larger, more fleshy cups; bluish grey in the Andamans.
• Lobophyllia corymbosa: Every cup has only one centre.

How to identify it

• A domed or flat colony with wide, fleshy, winding valleys.
• Valleys about 20-25 mm wide, often running out from the middle.
• A groove usually runs along the top of each wall.
• Walls and valleys usually in different colours.

Where to see it in the Andamans

Upper reef slopes and fringing reefs, from the surface to about 40 m. Recorded at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Sir William Peel, Wilson, Outram and South Button islands in a ZSI survey of Ritchie's Archipelago (as Symphyllia radians).

How it lives

In this group of corals the polyps come out only at night. Thick, fleshy tissue covers the skeleton by day.

Easy to confuse with

• Lobophyllia recta: Narrower valleys, up to 15 mm, that wind more.
• Lobophyllia agaricia: Wider valleys, about 35 mm.
• Greater Maze Coral: Much narrower valleys, not fleshy.
• Lobed Brain Coral: Separate fleshy lobes or short valleys, no groove along the walls.

How to identify it

• A mass of smooth, grape-sized bubbles by day.
• Grey, cream or bluish grey.
• The bubbles shrink only slowly, if at all, when touched.
• Under the bubbles: tall, widely spaced, smooth-edged plates of skeleton.

Where to see it in the Andamans

Sheltered reefs, often in murky water, at about 2-40 m. It is usually uncommon. Recorded at Rutland Island, South Andaman, and listed in Zoological Survey of India (ZSI) checklists for the islands.

How it lives

The bubbles (vesicles) are full of water and are blown up during the day. At night they go down and the tentacles come out to catch food.

Easy to confuse with

• Pearl Bubble Coral: Smaller bubbles that cover the whole colony and pull in when disturbed.
• Plerogyra discus: The closest look-alike in coral guides; not recorded from the Andamans in our sources.

How to identify it

• Small clumps of short, tube-shaped cups rising from one base.
• Cups orange to red, each up to about 11 mm wide.
• Grows in shade: walls, caves, overhangs, wrecks and jetties.
• At night the cups are hidden by rings of yellow to orange tentacles.

Where to see it in the Andamans

Shaded walls, caves, overhangs, wrecks and jetties, down to 43 m in the Andamans (mostly 6-10 m in South Andaman). Surveys from 2009 to 2016 found it at three stations around Havelock (Swaraj Dweep), and at Outram, Henry Lawrence, Inglis, Wilson, Shoal Bay, Rutland, Cinque and other sites. A 2014 photo record from Radhanagar Beach on Havelock also shows it.

How it lives

Unlike most reef corals, it has no tiny algae living inside it, so it does not use sunlight. It feeds only on tiny drifting animals caught with its tentacles. The polyps open mostly at night.

Easy to confuse with

• Black Sun Coral: Dark green to black, grows as a branching tree up to 1 m tall, with smaller cups.
• Dendrophyllia cup corals: Very similar; told apart by details of the skeleton.

How to identify it

• A single round or slightly oval disc, lying loose.
• Thin plates run out from the centre, with pointed, triangle-shaped teeth.
• Tall, smooth, cone-shaped spines on the underside.
• Up to 28 cm across; usually brown.

Where to see it in the Andamans

Reef slopes and lagoons, from the surface to about 50 m. In Ritchie's Archipelago, ZSI recorded it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Henry Lawrence, Outram, Inglis, South Button and John Lawrence islands. Also recorded at Rutland Island, South Andaman.

How it lives

It has short, tapering tentacles. Its skeleton grew about 2 mm a year in a study in the Maldives.

Easy to confuse with

• Lithophyllon repanda: Finer teeth on the plates. Also recorded in Ritchie's Archipelago (Wilson, Outram, Inglis and John Lawrence islands).
• Danafungia horrida: Often mistaken for it; check the teeth and the spines underneath. Also recorded at Havelock.
• Spiny Mushroom Coral: Long and oval, not round, with one groove along the middle.

How to identify it

• Thick, tube-like tentacles, out day and night.
• Each tentacle ends in an anchor-, hammer- or T-shaped tip.
• The tips are usually paler (cream or green) than the stalk.
• Under the tentacles: long, winding valleys with sharp walls.

Where to see it in the Andamans

Shallow reefs; ZSI notes it in calm, shallow water. Recorded at Rutland Island, South Andaman, and listed for both the Andaman and the Nicobar groups.

How it lives

Its big, fleshy polyps stay out day and night. Colonies are seldom more than 1 m across, but they can join into a cover many metres wide.

Heat, bleaching and threats

Listed as Vulnerable by the IUCN in 2008, then moved to Least Concern in 2023.

Easy to confuse with

• Frogspawn Coral (Fimbriaphyllia divisa): Same skeleton, but each tentacle ends in many small, branched knobs.
• Fimbriaphyllia paraancora: Same kind of tentacles, but grows as separate branches, not long valleys.
• Euphyllia glabrescens: Plain tube tentacles with round tips, no hammer shape.

How to identify it

• A bushy, tree-like colony up to about 1 m tall.
• Dark green to black, polyps and tentacles too.
• Branches 1-3 cm thick, usually facing across the current.
• Cups 6-8 mm wide, all along the branches.

Where to see it in the Andamans

Exposed surfaces and ledges, and also wrecks. In the Andamans ZSI notes it on vertical man-made structures and reefs with a soft bottom. Recorded at Havelock (Swaraj Dweep) in a ZSI survey of Ritchie's Archipelago, and also at Rutland Island, South Andaman.

How it lives

It has no tiny algae living inside it, so it does not use sunlight. It feeds on tiny drifting animals caught with its tentacles. In this genus the polyps open mostly at night.

Easy to confuse with

• Orange Cup Coral: Orange-red with yellow tentacles, in low clumps under 15 cm, with bigger cups.
• Black Coral: Thin, wiry or feathery branches with tiny polyps, not fleshy cups. A different group of animals.

How to identify it

• Thin plates that twist, fold and join like lettuce leaves.
• More upright in shallow water, flatter in deeper or shaded water.
• Small, crowded cups (about 2.5 mm) that stick out a little, so the surface feels rough.
• Grey-green or grey-brown.

Where to see it in the Andamans

Shallow reefs, often in murky water, at about 3-20 m. Recorded at Rutland Island, South Andaman. A 2014 review lists it from the Andaman group but not the Nicobars.

How it lives

Its shape depends on how much light reaches it. The algae in its tissue need sunlight to make food.

Heat, bleaching and threats

The IUCN rated it Vulnerable in 2008. The 2023 reassessment put it at Least Concern.

Easy to confuse with

• Yellow Scroll Coral: Yellow-green with a coloured rim, flatter plates and a smoother surface.
• Turbinaria frondens: A look-alike with bigger cups (about 3.5 mm). Small colonies are cup-shaped, then grow broad fronds.

How to identify it

• A long, loose, slipper-shaped colony on sand or rubble.
• Mouths spread all over the top, not only along a central groove.
• Many long tentacles with white tips, usually out by day.
• Sometimes shaped like a Y, T or X.

Where to see it in the Andamans

Reef slopes, at about 1-30 m, especially where mushroom corals are common. Recorded at Rutland Island, South Andaman. ZSI notes it on upper reef slopes in the Andaman and Nicobar Islands.

How it lives

One colony has many mouths spread over its top. Like its mushroom coral relatives, it lies loose and is not fixed to the reef.

Easy to confuse with

• Tongue Coral: A clear groove full of mouths along the middle, and short tentacles out only at night.
• Polyphyllia novaehiberniae: Its closest relative; told apart by skeleton details.

How to identify it

• A colony covered in long, flower-like polyps.
• Each polyp has a ring of tentacles around a mouth cone, often white.
• Goniopora columna grows as short columns.
• Goniopora albiconus forms thin crusts with very large white mouth cones.

Where to see it in the Andamans

Goniopora columna was recorded at Havelock (Swaraj Dweep) and Outram Island in a ZSI survey of Ritchie's Archipelago, and at Rutland Island, South Andaman. It is described as common, and forms large stands of one species, especially in murky water. Goniopora albiconus has only a few records from the islands.

How it lives

Each polyp sits in a small cup in the stony skeleton and can pull back into it.

Easy to confuse with

• Goniopora albiconus: Thin crusts with short polyps and very large white mouth cones. Underwater it looks like a patch of zoanthids.
• Zoanthids (button polyps): Soft animals with no stony skeleton, from a different group.

How to identify it

• A mass of small, grape-sized bubbles over the whole colony by day.
• Bubbles smaller than in bubble coral, and they pull in quickly when touched.
• Under the bubbles: a solid colony with short, widely spaced valleys.
• Pale grey, sometimes dull green.

Where to see it in the Andamans

Murky reefs, at about 1-20 m, often in crevices and under overhangs, especially where tidal currents run. Recorded at Sir William Peel Island in a ZSI survey of Ritchie's Archipelago, and at Rutland Island, South Andaman.

How it lives

The bubbles are blown up during the day. The tentacles come out only at night to catch food.

Easy to confuse with

• Bubble Coral: Bigger bubbles, the size of large grapes, that shrink only slowly, if at all.

How to identify it

• A long, loose, tongue-shaped colony with rounded ends.
• A groove runs along most of its length, with mouths inside it.
• Many smaller mouths outside the groove too.
• Some are forked into a Y, T or X shape.

Where to see it in the Andamans

Reef slopes and lagoons where mushroom corals live, at about 1-30 m. The Zoological Survey of India's survey of Ritchie's Archipelago found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Wilson, Henry Lawrence and South Button islands. Also recorded at Rutland Island, South Andaman.

How it lives

Its short, widely spaced tentacles come out only at night to feed.

Easy to confuse with

• Feather Coral: Mouths all over the top, and long tentacles out by day.
• Spiny Mushroom Coral: Usually only one mouth, and strong, spiny teeth.

How to identify it

• Flat plates, mostly level, sometimes stacked in tiers.
• Yellow-green with a clearly different coloured rim.
• Cups sunk into the surface, so the plate looks smooth.
• Cups widely spaced, about 2.5 mm wide.

Where to see it in the Andamans

Fringing reefs in murky water, usually at about 2-15 m. Recorded at Rutland Island, South Andaman, and listed for both the Andaman and the Nicobar groups.

How it lives

Colonies can grow up to about 5 m across.

Heat, bleaching and threats

The IUCN listed it as Vulnerable in 2008 and as Least Concern in 2023.

Easy to confuse with

• Salad Coral: Grey-green or grey-brown, with more upright, twisted plates and a rougher surface.

How to identify it

• Thin, flat plates, usually level.
• Fine ridges in rings, like the grooves of a record.
• No separate cups you can see: only ridges and narrow valleys.
• Pale brown to grey, often with paler edges.

Where to see it in the Andamans

All kinds of reef, most common on lower reef slopes, and recorded down to 88 m in the Coral Sea. In a survey of Ritchie's Archipelago, the Zoological Survey of India found it at Havelock (Swaraj Dweep), Neil (Shaheed Dweep), Sir William Peel, Nicolson, South Button, Sir Hugh Rose and John Lawrence islands. Also recorded at Rutland Island, South Andaman.

How it lives

Its cups sit in rows between the ridges, too small to see.

Easy to confuse with

• Pachyseris rugosa: Upright, crumpled plates and ridges.
• Pachyseris gemmae: The closest look-alike in coral guides.

How to identify it

• A long, oval coral lying loose on the bottom.
• Usually only one mouth, in a groove along the middle.
• Strong, spiny teeth on the plates.
• Often about 25 cm long; usually brown.

Where to see it in the Andamans

Reef slopes and sheltered lagoons, at about 1-20 m. Recorded at Havelock (Swaraj Dweep), Neil (Shaheed Dweep) and all the other islands in a ZSI survey of Ritchie's Archipelago.

How it lives

Like the other mushroom corals, it lies loose on the bottom rather than being fixed to rock.

Easy to confuse with

• Ctenactis crassa: A row of several mouths along the central groove. Also recorded at Havelock.
• Tongue Coral: Many mouths, in the groove and scattered over the surface.
• Common Mushroom Coral: Round, not long and oval.

How to identify it

• A hard, smooth surface covered in tiny pin-prick pores, with no coral cups.
• Fine hair-like polyps stick out of the pores.
• Shape varies: knobby lumps and crusts, upright joined plates, or net-like branches.
• Light brown, often with white growing edges.

Where to see it in the Andamans

Reef flats and upper reef slopes, from under 1 m to about 40 m, in both murky inshore water and clear offshore water. A 2009 snorkel and free-dive survey recorded Millepora exaesa on the reefs at Vijayanagar beach, Elephant beach and Radhanagar beach on Havelock (Swaraj Dweep), at about 3-10 m.

How it lives

Two kinds of tiny polyps sit in the pores. Short feeding polyps carry knobs full of stinging cells, and long thin polyps catch small prey. Fire coral also has tiny algae living inside it (zooxanthellae), which need sunlight.

Heat, bleaching and threats

It stings if touched, so keep hands, knees and fins away. If you are stung, rinse the skin with vinegar and leave any blisters alone. See a doctor for an open wound or a bad reaction.

Because it has these algae, it can bleach in hot water like hard corals. The IUCN lists every fire coral recorded in India as Endangered (reassessed in 2022, one species in 2024), because a steep decline is expected in future. Protected under Schedule I. Do not touch, break or take any piece, even dead coral.

Easy to confuse with

• Hard corals: Hard corals have small cups (corallites) on the surface. Fire coral is smooth, with only tiny pores.

How to identify it

• Solid lobes or columns that look like a hard coral.
• The living surface is brownish.
• Where a branch has broken, the skeleton is bright blue.
• The surface has small pores, with no coral cups.

Where to see it in the Andamans

Reef flats, the zone exposed at low tide and other shallow reef areas, mostly in less than 2 m of water. It lives only where the water stays above 22°C all year. It was recorded at the Vijayanagar, Elephant and Radhanagar beach reefs on Havelock (Swaraj Dweep) in a 2009 survey, and in a 2018-19 CMFRI survey that covered Havelock, Neil (Shaheed Dweep), North Bay and Wandoor.

How it lives

The polyps live in small tube-shaped pores in the skeleton, linked by smaller tubes. It has tiny algae living inside it (zooxanthellae), so it depends on light.

Heat, bleaching and threats

Because it depends on these algae, it can bleach in hot water. Protected under Schedule I.

Easy to confuse with

• Lobed or column-shaped hard corals: Hard corals have small cups on the surface. Blue coral has only fine pores, and its skeleton is blue where broken.

How to identify it

• A mound or crust of upright red tubes joined by flat cross-plates.
• When alive, the tubes are hidden by a carpet of feathery polyps.
• Each polyp has eight feathery tentacles.
• The polyps pull back into the tubes when disturbed, and the red skeleton shows.

Where to see it in the Andamans

Many kinds of reef, but much less common in muddy coastal water. On the Great Barrier Reef it becomes more common with depth, down to about 20 m. A Zoological Survey of India report names it among the most common reef builders on the Nancowry reef platforms in the Nicobar Islands, and records list it for the Andaman and Nicobar Islands without exact sites.

How it lives

Each tube is built and lived in by a single polyp, which can pull right back inside. The polyps have tiny algae living in them (zooxanthellae).

Heat, bleaching and threats

It is over-collected in some regions.

Easy to confuse with

• Clavularia, Sansibia and Anthelia (soft corals): With the polyps open they look alike. Only organ-pipe coral has the red tube skeleton underneath.

How to identify it

• Looks like a bush, a feather or a single long wire.
• Wire corals are single, unbranched whips.
• The skeleton inside is black to golden-brown and covered in tiny spines.
• Each polyp has six plain tentacles that cannot pull back in.

Where to see it in the Andamans

Hard surfaces with low light and strong current. A few live from about 2 m, but in the tropics most are found below 50 m. A Zoological Survey of India diving survey in 2009-2011 found eight black corals new to India. At the Wall dive site off Havelock (Swaraj Dweep) it recorded the wire coral Cirrhipathes anguina at 5-10 m and Myriopathes antrocrada at 25 m. The other sites were Long Island, Pongibalu (South Andaman) and Kamorta (Nicobars).

How it lives

Black corals catch tiny drifting animals (zooplankton) with their polyps. Unlike hard corals, they generally do not depend on tiny algae living inside them. Shallow wire corals can grow fast: one in Indonesia grew up to 13 cm in a month.

Heat, bleaching and threats

Protected under Schedule I. Do not touch, break or take any piece, even dead coral.

Easy to confuse with

• Sea Whip: Sea whip polyps have eight feathery tentacles. Black coral polyps have six plain ones.

How to identify it

• A bare stalk topped by a wide fleshy disc.
• Older colonies have a wavy, folded edge.
• Polyps grow only on the top of the disc.
• With the polyps pulled in, the top looks smooth and leathery.
• Brown, beige, yellow, green or cream.

Where to see it in the Andamans

Reef flats and slopes, from muddy coasts to offshore reefs. A 1991-92 survey found dense mats of Sarcophyton trocheliophorum at 2-5 m at Wandoor, and Sarcophyton at Carbyn's Cove, Chidiyatapu, Digilipur and Mayabunder. Sarcophyton birkelandi was first recorded in India from Craggy Island in 2017.

How it lives

Each colony has two kinds of polyps: long feeding polyps up to 20 mm, and tiny pore-like polyps between them. The feeding polyps can pull right in, leaving the top smooth. Tiny algae living inside the coral (zooxanthellae) need sunlight.

Heat, bleaching and threats

It can bleach in hot water. Bleached leather corals may live on for weeks to months, shrinking while they wait.

The Wild Life (Protection) Act puts soft corals of the families it names in Schedule I. This genus was in one of them (Alcyoniidae) when the list was written, and the Zoological Survey of India counts it as Schedule I.

Easy to confuse with

• Lobed Leather Coral: A thick crust with lobes and ridges on top. It has no clear stalk and disc.
• Finger Leather Coral: Grows as knobby crusts, fingers or branches rather than a smooth disc on a bare stalk, and has only one kind of polyp.

How to identify it

• Very variable: low crusts with knobs, tall finger-like lobes, branches or leaf shapes.
• Tough and hard when the polyps are pulled in, because of chalky spicules inside.
• Small polyps, often the same colour as the colony.
• Brown, yellow, green or cream; polyps sometimes white or yellow.

Where to see it in the Andamans

Almost every kind of reef, from murky bays to clear water, down to at least 40 m. Some species live on reef flats and survive being exposed at low tide. In March 1992, six species were collected on Havelock (Swaraj Dweep) from the low-tide zone to 5 m, and the group was also found at Digilipur, Mayabunder, Rangat, North Bay and Chidiyatapu.

How it lives

The polyps are small and short and can pull right in. Like the other leather corals, it has algae inside that need sunlight.

Heat, bleaching and threats

It can bleach. One bleached colony was still alive two months later, though it had shrunk.

The Wild Life (Protection) Act puts soft corals of the families it names in Schedule I. These genera were in one of them (Alcyoniidae) when the list was written, and the Zoological Survey of India counts them as Schedule I.

Easy to confuse with

• Lobed Leather Coral: Its lobes are more regular, and it has two kinds of polyps.
• Mushroom Leather Coral: Has a bare stalk and a wide disc on top.

How to identify it

• A thick, firm crust with polyps only on the top.
• The top has finger-like lobes or ridges, sometimes like a cock's comb.
• Tips of the lobes are often paler than the sides.
• Usually yellow-brown; polyps white, yellow or greenish-brown.

Where to see it in the Andamans

Shallow, well-lit reef flats, crests and upper slopes, down to about 25 m in clear water. It is rare in muddy places. In the Andamans it has been recorded from the low-tide zone to 4 m at Wandoor, North Bay, Burmanallah, Chidiyatapu, Mayabunder and Digilipur, and museum specimens come from Neil (Shaheed Dweep).

How it lives

It has two kinds of polyps: large feeding polyps up to 10 mm, and tiny ones between them. Offshore species rarely open their polyps by day.

Heat, bleaching and threats

A 1996 study remarked that Lobophytum pauciflorum is rare on Havelock's reefs. It blamed the lack of rock and the over-exploitation of stony corals there.

The Wild Life (Protection) Act puts soft corals of the families it names in Schedule I. This genus was in one of them (Alcyoniidae) when the list was written, and the Zoological Survey of India counts it as Schedule I.

Easy to confuse with

• Mushroom Leather Coral: Has a stalk and a wider disc. Odd-shaped colonies need a microscope to tell apart.
• Finger Leather Coral: Has one kind of polyp and less regular lobes.

How to identify it

• A bushy, see-through "tree" with bright bunches of polyps at the branch tips.
• Looks spiky, from large spicules beside each polyp.
• Swells up with water to feed, at night or in strong current.
• Shrinks to a small lump when contracted.
• The stalk is often pale.

Where to see it in the Andamans

Mostly below 20 m on slopes and walls with strong current, and shallower on steep walls. It also lives in muddy estuaries. Species such as Dendronephthya andamanensis and D. nicobarensis were described in 1909 from material collected by the survey ship Investigator, but those old records give no exact sites.

How it lives

Bundles of 2-15 polyps sit on the twigs and cannot pull back in. They open at night and in strong current. With no tiny algae inside, it does not depend on light and filters its food from the water.

Heat, bleaching and threats

Schedule I covers it because it belongs to the family Nephtheidae.

Easy to confuse with

• Other tree-like soft corals (Scleronephthya, Nephthea, Stereonephthya): Hard to tell apart without a close look at the polyp bundles and spicules.

How to identify it

• A large, flat fan with a dense net-like mesh of joined branches.
• Some fans have long, stretched meshes; others have finer, many-sided meshes.
• Small polyps all round the thin branches.
• Yellow or pinkish-yellow; looks orange or brown when the polyps are open.

Where to see it in the Andamans

Reef sides and ridges with strong current, below the reach of storm waves. It is absent from places with big waves or weak current. Photo records from Havelock waters (2025) show this genus.

How it lives

It has no tiny algae inside, so it does not depend on sunlight. Its small polyps can pull in, and they filter food from the water.

Heat, bleaching and threats

Its family, Subergorgiidae, is named in Schedule I, so it is protected.

Easy to confuse with

• Other net-like sea fans (Melithaeidae): Their core is jointed, with nodes. Giant sea fans have a smooth, horny core.

How to identify it

• Junceella: one unbranched whip, can be over 2 m long.
• Ellisella: a bush of long whip-like branches, up to at least 1 m.
• The polyps cannot pull fully in.
• Closed polyps form bumps, like small snake heads, along the whip.
• Red, orange, yellow-brown, beige, grey, yellow or white.

Where to see it in the Andamans

Muddy bases of reefs with strong current, and deeper reef slopes. Ellisella is rare above 5 m. Ellisella andamanensis was described from the Andamans, and a 2024 photo record shows Ellisella at Havelock (Swaraj Dweep).

How it lives

Sea whips have no tiny algae inside, so they do not depend on sunlight. They filter food from the water with polyps all round the whip or in a few rows.

Heat, bleaching and threats

Protected under Schedule I, as a member of the family Ellisellidae.

Easy to confuse with

• Black Coral (wire coral): Wire coral polyps have six plain tentacles. Sea whip polyps have eight feathery ones.
• Viminella and Dichotella: Look the same underwater. Only experts can separate them, using spicules.