The Indo-Pacific coral reefs are homes to the most prolific congregation of lifeform under the sea. The ecosystem is so intricately interwoven; many researchers claim is rivalled only by tropical rainforests the likes of the Amazon, the Congo and the Malaysian Rainforests.

Journeymalaysia has come up with a list of the more common fishes found in our waters, exploring the fishes' behaviour and their contribution to the environment. However, there are so many species we simply cannot accommodate each and every one. There are a number of good references that can be purchased at bookstores such as Times and Kinokuniya at Suria KLCC in KL.
A good reference on understanding reef fish behaviour , titled :- Pisces Guide to Watching Fishes: Understanding Coral Reef Fish Behaviour by Roberta Wilson and James Q. Wilson.

Damsel

The most prolific little fishes found on reefs. There are about 150 species of Damselfish in South East Asia. Damselfish are fiercely territorial and some species cultivate small algal crop sometimes as large as 1sq m. It defends its 'farm' from intruders such as sea urchins which graze on the algae. They spend much of their energy patrolling their little plot of grazing land and often can be seen chasing off larger herbivorous or omnivorous fish. Damselfish like the black farmer fish (Stegastes lividus) only works its farm during the day but there's no worry during the night of any marauders as other algae-grazers are also diurnal; that is, they go to sleep when the sun sets. As the sun goes down, the damselfish retreats into its cubby hole for the night.

Most types of Damselfish are nest builders. Usually the male undertakes this task and the guarding of eggs. The male searches for hard rock surfaces for its nest site then begins cleaning the area of algae and debris. Sometimes they can be seen dragging larger pieces of broken corals away from the nest. When the nest is ready, the male changes its colour and swims frenetically around making clicking sounds in an attempt to lure as many ripe females as possible to his 'lovenest'. As soon as the eggs are deposited, the female is chased away by the male. And the mating cycles may continue with the same ripe female or several other ripe females until his nest is filled to the brim with eggs.

Sergeants are one of the few fishes which are circumtropical, that is, they are found on virtually every reef from the Red Sea and the East African Coast to South-eastern Polynesia and North Japan. Sergeants from the tropical Atlantic and Panamanian are virtually indistinguishable apart from very subtle colour pattern differences .The Indo-Pacific sergeants travel in large aggregations of a 100 individuals or so. They are most often found in sheltered reef areas or in the outer slopes of the reef. During spawning season, the male prepares the nest by fanning water into little nooks found on the hard bottom, clearing it of algae and debris. Then he would invite ripe females to his nest by performing an intriguing zigzag dance. Sometimes the male invites other ripe females to its nest just to accumulate a mass of eggs, which can amount to 25,000 per season. Then the male ferociously guards his amassed treasure until they are able to school protectively on their own.

The chromis is also a common reef fish and they stick in large groups usually around branching corals such as the acropora genus. These tiny fishes of roughly 9cm in length and they feed on zooplankton that drifts with the current. Chromis' routinely change their colouration to blend in the background. These planktivores may move to the edge of the reef to feed in the currents. Away from the safety of the corals, they blend in with the monochromatic hue of the open sea. As they swim back to the corals, they darken to match the colours of the surroundings.

A single male may attract up to 20 females to his nest through a complicated dance movement consisting rapid up and down swimming. Several thousand eggs are laid during this mating season and are guarded by the male for 2 - 3 days until they hatch. After hatching, the larvae will drift up to the surface where it mixes with all the other planktonic life forms circulating around the reef for 18- 24days before reaching adulthood.

This fish can be mistaken for its close relative, the neon damsel which is found throughout South East Asia. The slight difference is that the goldbelly has more yellow on its body and fins and are found predominantly in the Malay-Indonesian Archipelago. Goldbelly damsels are found in outer reef areas in clear waters, frequently playing among coral rubble. Their depth ranges between 1m and 12m.

Lemon Damsels are found on coastal areas, shallow waters in lagoons and outer reefs, hovering over living corals where they feed on drifting zooplankton, algae and small invertebrates. They are normally seen between 1 to 14m and form large groups around individual coral formation where they can slip through the mesh of branches and interlocking web of hard corals when challenged with danger. They float up again above the corals when danger has past to continue feeding. Lemon Damsels are one of the most abundant Damselfishes on the reefs and sometimes through the corner of the mask, one can catch glimpses of the bright yellow bodies glittering in the sunrays. Like a mirage, as one gets closer, it disappears as one gets closer! As one swims away, the tiny fishes float up again like a sheet of mist hanging over the coral formations.

Humbugs are one of those species that are a little fussier in their living abodes. They prefer the table corals of the acropora sp. where, at any sign of danger they can safely slip between the branches of the corals. As danger passes, the Humbugs rise up just above the table corals again to continue feeding on the plankton brought in by passing currents. This works well for the little fish as they do not have to run the risk of migrating to the edge of the reef to feed, exposing themselves to the hungry predators circling around. Humbugs sometimes live amongst sea anemones together with clownfish but rather prefer to make their homes in finger corals interspersed with sandy patches.

Humbugs can live together making up several social units in the community. They can live in small harems dominated by a large male and aided by a large female or live in large polygamous groups or in heterosexual pairs. Just before spawning, the male searches for a nest site at the dead base of the coral head. Having selected the most appropriate, it begins to chew the filamentous algae enwrapping the stem. When he is satisfied with the condition of the nest site, he will then invite the females to mate with him by displaying a series of jerky up and down movements. Once the eggs are laid and the female is banished from the area, the male settles down to look after the eggs until hatched.

Anemonefish is a subfamily of the damselfish. A British naturalist, Dr. Cuthbert Collingwood was the first European to witness and describe the anemonefish's association with sea anemones 128years ago off the shores of Borneo. There are 28 known species spread across a wide area from the Indo-Pacific to East Africa and the Red Sea toward Polynesia.

Most species have distinct colour patterns of orange, red or black background with bands of white vertical stripe markings. Anemonefish are poor swimmers with no defensive mechanisms except for its immunity to the sea anemone's sting. Therefore Anemonefish are never found without its host, the sea anemone.

The sea anemone's tentacles are packed with microscopic stinging cells called nematocysts. The Anemonefish has to acclimatise itself to these stings. To do so, the fish nibbles at the tentacles, touches the tentacles with its pectoral fins and tails, gets stung momentarily, retreats to come back for more. This process takes a period of several minutes to several hours where each time it is stung, it triggers some sort of change in the mucus coating covering its body. After a series of such sessions, the fish becomes immune to the toxins of the anemone and can then live comfortably in its new found home. It was found through some lab experiments that if the fish is separated from its anemone for more than 24hrs, it will have to go through the acclimation process again.

Besides receiving protection from the anemone, the fish also gets to feed on bits of the anemone's prey and waste material and may possibly even receive some form of resistance from certain diseases. In return, the Anemonefish defends its home aggressively from larger fishes such as Butterflyfishes and wrasses who feed on the anemone. It also removes waste material from the anemone and sometimes deposit morsels of uneaten food in it and possibly remove parasites from it. Many researchers maintain that this form of commitment to each other skew more towards the fish than otherwise. They believe that it is most unlikely that the fish can survive without its anemone but that the sea anemone can continue to live without the fish and consequently this sort of arrangement was called 'facultative symbiont'.

However, new findings revealed that perhaps the anemonefish can live without a host. They have been seen on occasions to swim freely in the coral reef. Apart from being a latch-on as many believe them to be, the anemonefish is beneficial to the anemone as lures. The white iridescent markings on its body acts like bait eg worms wriggling around within the tentacles of the anemone. Curious fish dive down to investigate and eventually is paralysed by the anemone's stings so becomes food for the happy family. If you watch closely, you will see the anemonefish wiggling their bodies at the edge of the tentacles - trying to lure unsuspecting fish to their doom.

The Anemonefish of the genus Amphiprion common in the Indo-Pacific waters are predominantly monogamous. The Tomato Anemonefish (Amphiprion frenatus)- 8cm, Pink Anemonefish (Amphiprion perideraion)- 8cm, Clark's Anemonefish (Amphiprion clarkii) - 10cm and the False Clown Anemonefish (Amphiprion ocellaris)- 8cm are examples of this genus found in these waters. The fish lay several hundred eggs at the base of the anemone just under a veil of protective tentacles, sometimes nibbling the bottom tentacles to expose the nest.

After the eggs are deposited, the male will fiercely guard them for 7-8days, periodically fanning and mouthing the eggs. The eggs hatch during periods of full and new moons where the currents are swift and the waters are high, presumably to quickly disperse these planktonic larvae to new sites. The larvae are exposed to the open for 1-2weeks until they find a new anemone or die.

 

Butterflyfish

These beautiful fish can be seen flitting around in shallow reef areas. The colours are vibrant consisting shades of yellow, orange, white with prominent markings like spots, stripes or bands or even a combination of patterns. Some of these markings are significant as a form of defence such as a pair of brown or black spots at the base of its tail. These 'false eyes' dupe predators into thinking that the tail end is the head of the fish and as most predators swallow their victims' head first, they would naturally target for the eye. Whereas the band across the fishes true eyes camouflages them. Somewhat like some camouflage patterns found in cerain species of butterflies. Butterflyfish have excellent vision. Their flexible eyes are supported by powerful , complex muscles, which provide them with good focussing ability. The eyes are set well forward and close together on their heads that gives them a wide visual field. Most fish can recognise colours. Among vertebrates, they share the same attributes only with primates (man, apes, monkeys), lizards, turtles and birds or so it seems. This makes a lot of sense in an environment such as the ocean where differentiating colours may mean getting food or being food.

Butterflyfish's diet consists mainly of coral polyps, tentacles of featherduster and Christmas tree worms. These food items do not swim away but retreat into their shells when in danger. Through years of evolution, the butterflyfish have adapted the ability to hover motionless while nipping at the corals. Divers and snorkellers will get the chance to watch the butterflyfish flutter around corals, darting swiftly over short distances, to catch the odd Christmas-tree worm before it retracts.

Chaetodontidae is derived from a Greek word, which means 'bristle tooth'. A prime example of such a species is the longsnout butterflyfish. As the name suggests, it has a delicate long snout which enables them to extract small invertebrates such as tubeworms, coral polyps, algae, tunicates and sponges from crevices too deep for other fishes to get at. Sometimes it even nibbles on tube feet and other appendages of spiny sea urchins.

The fish's flattened body allows it to slip into narrow crevices when threatened and is propelled with the rowing motion of the pectoral fins. These fins may not be of use for bursts of speed but they are invaluable for complex manoeuvres such as backing, braking and pivoting. Butterflyfish are generally 'home-ranging'- they live, feed and breed on individual reefs. During the day, they feed on the corals within the confines of their range and at night, they retreat into crevices to sleep. They can erect their dorsal and anal spines to wedge themselves firmly inside the crevice especially when provoked. So be careful not to grab at them, the spines can pierce through gloves.

Most butterflyfish species live in pairs. Sometimes the bond between pairs can be so tight that if they become separated, one member will stop foraging to look for its wandering mate. When found, it swims quickly in a straight line to rejoin its mate and celebrate their reunion by swimming around each other at very close range for a few minutes, often tilting their bodies toward each other. This strong bonding can be seen in species such as the saddled butterfly (chaetodon ephippium).

Some of the fine examples of butterflyfish found in Malaysian waters are, racoon butterflyfish(Chaetodon lunula) - 18cm, pacific double-saddle butterflyfish(Chaetodon ulietensis)- 14cm, longsnout butterflyfish(forciper sp) - 18cm, Bennett's butterflyfish(Chaetodon bennetti) - 16cm and the bannerfish(Heniochus sp)- 25cm.

The bannerfish differs from the general body structure of the genus Chaetodon in that the anterior part of the fin is elongated…forming an antenna-like appendage. The Longfin bannerfish(Heniochus acuminatus) and the Schooling bannerfish(Heniochus diphreutes) can be differentiated on the basis of behaviour rather than physical markings. Both have black and white bands painted vertically on the body with long backflowing, trailing filament lifting off the dorsal fin. They have the same dietary preferences, feeding mainly on zooplankton, worms and shrimps. The difference is that Longfin bannerfish are found either on its own, in pairs or small groups, usually sniffing around on the bottom. The schooling bannerfish however, move around in large groups usually swimming high above the bottom. Sometimes these fishes can be mistaken for Moorish Idols.

Angelfish

Angelfishes and butterflyfishes are members of the same family, Chaetodontidae, a Greek word meaning, "bristle tooth". Quite often mistaken for its close relative the butterflyfish, due to the vibrant colours, distinctive markings and slender disc shaped body structure. Upon closer inspection, one can see a prominent enlarged, backward protruding spine on the lower edge of the gill cover. The sharp spine is used as a form of defence.

The confusing patterns of bars and spots combined with the brilliant colours of the Angelfish and butterflyfish protect them from their predators. The bars on the body disrupt the body's outline. These patterns plus their ability to pivot and manoeuvre in erratic manners make confusing visual targets for predators who are hot in pursuit during a chase. Researchers have remarked that the coloration of such species seem to work as the angelfish and butterflyfish are less likely found in the stomach contents of predators than other prey.

There are about 85species of angelfishes found in the tropical seas. Their length range between 7 to 50cm. Spawning occurs at dusk and usually occurs in pairs. Breeding males may mate with different females during spawning periods. Males defend their spawning areas from other males, chasing them away as soon as they encroach into their territories. They then swim away from the bottom to greet wandering females or wait for them to pass by. When a ripe female arrives, the male performs a courtship dance with a combination of movements such as fin erection, body 'quivering' and swift back and forth swimming. Once the female succumbs to the impressive display, the pair spirals slowly towards the surface, depositing eggs and sperm at the end of the ascent. The eggs are fertilised and within 15 to 20 hours the eggs hatch, creating another generation for the survival of the species.

Species found in our waters are the Blue-ringed Angelfish(Pomacanthus annularis) - 27cm , Emperor Angelfish(Pomacanthus imperator)- 35cm, the Yellowmask Angelfish (Pomacanthus xanthometopon)- 35cm, Regal Angelfish( Pygoplites diacanthus) - 23cm and the Blue-girdled Angelfish (Pomacanthus navarchus) - 28cm

Surgeonfish

Surgeonfishes are one of the most difficult reef fishes to photograph. They shy away from divers and the juveniles hide among branches of live corals when they detect any sign of danger. Like many of the reef fishes, the surgeonfish has a slender shaped body so that they can squeeze into cracks in boulders when pursued by predators. Their oarlike pectoral fins are designed to provide them manoeuvrability and not so much for speed.

Most surgeonfishes are decorated with electrifying colours and are some of the more colourful and exquisitely patterned reef fishes found in Malaysia. The distinctive colours and patterns have shown that not only are they applied for camouflaging but also used as a form of communication. Researchers have found that certain species of surgeonfishes exhibit colour expressions during bouts of aggression. In an experiment, a Blue-striped Surgeonfish was put to test with another. Both displayed a series of colour change during the fight. The central caudal fin patch turned from black to white and its erected dorsal fin displayed a blue margin and stripes. The rest of the body adopted an overall darker coloration.

Surgeonfish are often seen on its own, in shallow waters on coral flats. They are sometimes found feeding in large aggregations. These groups of herbivores have often been viewed to be destructive to the reef areas. However, herbivores are important to the ecosystem. By breaking down the almost indigestible plant material, they provide nutrients for other animals. Moreover, they help control the spread of plants in the reef area which without these grazers, may take over the whole reef in a short time. Plants grow quickly sometimes crowding out the space for coral growth, which makes new coral settlement impossible.

All surgeonfishes have a powerful defence tool. They have one or two pairs of scalpel-like knives on either side of the base of their tails. Some species have patterned markings around these scalpel-like blades as warning coloration. The Palette surgeonfish (Paracanthurus hepatus) display a bright yellow tail in contrast with its blue and black body.

An incredibly shy creature, the palette surgeonfish is difficult to approach. Generally found in small groups on outer reefs and channels where currents are strong. It feeds in midwater but stick closer to coral patches where they safely slip into to escape danger. The Palette surgeonfish has a single collapsible scalpel-like blade at either side of the tail base. The spikes can be erected at right angles to the body when threatened. Danger passes and the fish relaxes, folding each spine into a shallow groove.

This beautiful surgeonfish is relatively common in the Indo-Pacific waters. Often found in shallow reefs where their food supplies, zooplankton is churned up by constant wave action.
The striped surgeonfish differs in other surgeonfish species in two manners.

One is that it is fiercely territorial of its domain, which can cover about 6-8sq. m. It attacks mainly grazers such as triggerfishes, parrotfishes and other surgeonfishes. In this way, it can safely manage its own patch of algae and have sufficient supply for itself to graze. Its aggressive behaviour is very apparent especially the changes in coloration. Researchers have found that the Blue-striped Surgeonfish displayed a series of colour change during a fight. Its central caudal fin patch turned from black to white and its erected dorsal fin displayed a blue margin and stripes. The rest of the body adopted an overall darker coloration.

The other peculiar differentiation from other surgeonfishes, is that the spines at the base of the tail is poisonous and can cause a painful wound if not handled properly.

There are 17 species of unicornfish in the genus Naso that are members of the surgeonfish family. The unicornfish differs from other surgeonfish sp. in that the one or two spines at the base of the tail are permanently fixed and not collapsible, as do the other surgeonfishes.

The spotted unicornfish is easy to distinguish from the other reef fishes. As its namesake, this fish has a pronounced horn growing from its forehead. The nasal horn only starts developing much later in life as it develops into adulthood. The dark spots and broken lines running down the side of the body are a dead give-away for the spotted unicornfish.

Unicornfishes often spawn in groups. The males exhibit courtship coloration to entice females to mate with them.

When I first saw a live Toucan face to face, I was in awe. It looked like a piece of sculpture a painter has spread his choice of colours on like he would on a canvas. The pastel colours seemed so unreal. Not too long, I saw that again. This time I saw the apparition in a different form. In the form of a unicornfish. The Yellowkeel as seen in the picture, is one of the most well-painted species of reef fishes. There is a pair of erect and fixed spine at the base of its tail, which functions as a defence tool.

The Yellowkeel is often sighted alone or in small groups and are generally home-ranging. They each patrol their own section of the reefs. These Unicornfishes feed on sea weeds and other sea plants.

Seldom seen without its partner, the Foxface cruise around the reef area in pairs. There are 28species in the Siganidae family and are all confined to the Indo-Pacific region.

The Foxface is easily recognisable. They are called Rabbitfishes because of its facial similarities eg their rabbit-like snout. These beautiful masked denizens of reefs in Malaysia are in fact, close relatives of the surgeonfishes. As we have read about the surgeonfish with its sharp scalpel-like blades on the sides of its tail, the Foxface has an outer and inner spine strengthening the structure of its pair of pelvic fins. These spikes and those of the dorsal and anal fins are poisonous. Rabbitfishes should never be handled, as the spines are capable of inflicting painful wounds although not as severe as those caused by scorpionfishes.

The juveniles travel in schools feeding on sponges, algae and sea squirts. But as they grow into adults they bond in pairs for life.

The Moorish Idol is also close relative of the surgeonfish. This is one of the most readily recognisable denizens of the coral reef. No wonder , since it is found everywhere in the Indo-Pacific, from the Red Sea, Persian Gulf, East Africa all the way to Central America. Swims around shallow water in singles or in small groups. The spawned eggs are left to drift with the currents. As it has been found in such vast geographical span, some researchers have theorised that the larvae travels with currents to the far reaches where they start their lives in different reefs from their parents. It is approximated that the larval stage extends 6 - 8 weeks. The transparent larvae can grow to 8cm in length. The shimmer of light just below, draw the larvae to the bottom. Once settled on the bottom, the larvae assume their typical colour pattern

Illustrations provided by Dennis Ho: Underwater photography by Moti Uttam

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