Filefish
The tough, rough leathery texture of the Filefish (also known as leatherjackets in Australia) skin was dried in the sun and used by South Sea islanders as sandpaper, hence its namesake. Filefishes are close relatives of the Triggerfishes and often found feeding in coral areas of depth between 1 and 30m. The Coral Filefish has an elongated snout and is covered with bright orange spots. Filefishes are recognised by the long dorsal fin just above the eyes that has been reduced in shape to spines. They are often seen around table corals, scouting the area in pairs.
Trevallies or Jacks
Jacks are among the most active reef predators. They patrol the reefs rigorously in small groups, on the lookout for food and are particularly active just before dusk and just after dawn taking advantage of the fishes returning to or leaving their safety holds. There are two types of hunters: those that pursue their prey and those that rely on the element of surprise through concealment or by deception. Jacks fall in the category of pursuers. Their forked tails reduce drag, the torpedo-shaped body to slice through water and the narrowed portion of the body that connects with the tail which minimises recoil - all aiding the jacks in conducting high speed chase.
A study by Geoffrey Potts on jacks found that these fishes hunt in-groups when patrolling off the reef slopes and hunt alone on shallower inshore areas. There seems to be 4 phases in their hunting behaviour. Patrolling, when the jack swims around the area but makes no predatory moves. Quartering, when the jacks make a series of zigzag moves at high speeds. Hunting, when the prey has been identified and the swimming movements increase in speed. Attacking, when the jacks homes in for the kill. According to Potts, fishes that are on the jacks' food list are aware of the four phases. The prey ignores the jacks at the patrolling stage. As the quartering began, the potential preys scatter into hiding places. Once there is a kill, the other fishes would come out of their hiding holes and resume foraging.
Jacks form schools for feeding purposes whilst the anchovies they like to feed on form schools for defence. A single jack was observed during attacks on anchovy schools. As the jack approached, the anchovies compacted into a more solid mass and begin swimming in a 'weaving pattern'. The jack attacks, the school parted with each half swimming round the Jack and fusing again at the Jack's rear. But if there were to be a second jack tailing the first, the chances of picking some laggards or some that swam out of sync would increase.
The Bigeye Trevally hunts at night or during twilight. They are good table fishes with a nice size that guarantees a good fight for anglers. The juveniles live in estuaries where these natural nurseries are a safe hold from predators and have abundance food blown in from the trees overhanging the areas and nutrients washed in from the land. Most species are piscivores but some eat mainly crustaceans and molluscs.
Other Trevallies found in Malaysian waters are the Golden Trevally, Bluefin Trevally (Caranx melampygus), the Horseeye Jacks (Caranx latus).
Snappers
Snappers are another common predatory fish found on reefs. The two-spot red snapper (Lutjanus bohar) is a favourite table fish in Malaysia and is often prepared in curry especially in the ever-popular 'Fish Head Curry'. But many eople do not realise that the Snapper is prone to ciguatoxic poisoning. Ciquatera is a toxin produced by a type of algal scum (dinoflagellate) found on certain reefs. The amount of toxin in each organism in itself is negligible. But when the algae along with the dinoflagellate is eaten by the reefs' herbivores and omnivores which in turn is eaten by piscivores such as groupers, barracudas, large jacks, some Triggerfishes, moray eels and snappers, the toxin is accumulated in the food chain. The toxin can not be destroyed through cooking or any other form of preparation. When we eat carnivorous fishes contaminated with Ciguatera toxin we may experience numbness in hands and feet, disorientation, vomiting, diarrhoea, shortness of breath, weakness and even cardiac arrest. In 1998, 19 cases of Ciguatera poisoning were reported in Hong Kong. But one thing is certain; those fishes came from this part of the world.
This snapper is so-called because of its red coloration and the two white pearly spots found on its dorsal fin. Many Snappers are nocturnally active, which means they feed at night. The large eyes are indications that these fishes hunt at night; they need to capture as much light as possible. They feed mainly on crustaceans and small nocturnal fishes like cardinalfishes, squirrelfishes and grunts that come out during the night.
The Paddletail Snapper is frequently seen in clear waters on outer reef slopes. Snappers are differentiated from other of similar families by the numerous scales on their cheeks. Most snappers have canine-like sets of teeth and 10 dorsal spines line the backbone.
The midnight snapper can be seen on the upper reaches of reef walls and slopes. Snappers get together in schools during the day for safety against its potential predators such as the jacks, barracudas and sharks. The snapper may follow sharks and barracudas to keep an eye on them but seldom are worked up to react. However, when jacks turn up, the snappers get agitated and the school moves closer together. Snappers as like all other reef fishes can distinguish between just large fishes and dangerous large fishes and are wary of their movements.
Scorpionfish
The Scorpionfish is found lingering at the bottom where coral formations are aplenty. Their ability to blend themselves completely into their environment is useful in capturing unsuspecting prey wandering into their domain. The Scorpionfishes are masters of disguise. As bottom dwellers, many Scorpionfishes do not have swim bladders at all, maintaining the negative buoyancy they require, to stay motionless on the seabed. Their indistinct shape makes it easier to mimic rock surfaces, sponges or in greenish-blue algae patches.
Due to its widely publicised reputation as one of the most poisonous creatures in the sea, it has hardly any predators even humans! The Scorpionfish and Lionfish have a row of poisonous spikes on their backs. The poisonous spikes if brushed against can cause excruciating pain but the poison is not enough to kill an adult. The best treatment is to immerse the inflicted area in hot water. The heat will break down its poison.
However another species called the Stonefish (Synanceia verrucosa), has created some sensational news regarding several deaths caused by these illusive creatures. These animals are very difficult to spot, therefore Divers! Try not to grab onto holds on rock surfaces if you can help it.
The Lionfish are nocturnal and therefore are often seen in the day, napping under ledges, in caverns and in wreckage either on its own or in small groups. They feed mainly on small fishes, crabs and shrimps that come out during the night. The Lionfish fans their long featherlike pectoral fins to corner its prey, whereupon it makes a quick dash forwards, inhaling the prey whole in one breath.
The dorsal, pectoral and anal fin spines are 'dripping' with poison and puncture wounds inflicted by these creatures are extremely painful. If you are unfortunate enough to have such an encounter, immediately immerse the wounded area in hot water. The pain will subside in due time.
The Scorpionfish is covered over with flaps and folds, which gives it an indistinct shape that can blend into the environment. The flaps and folds help its camouflage, looking like a growth of filamentous seaweed from it body and head. It lays motionless in its hold, and patiently waits for its prey to pass by within close range. The Smallscale Scorpionfish opens its mouth and with lightning speed, sucks in its prey in one breath. Like the Lionfish, the Smallscale Scorpionfish also produces poison as a form of defence. This protein-based poison is produced in the skin cells along the grooves found on the spines. This poison is if fact, heat sensitive and applying hot water to the wound will help the pain subside.
The leaf Scorpionfish is so named because it is almost leafy thin and gently sways in the current like a piece of dry leaf. What lures the prey towards the scorpionfish is it jewelled eye. The eye 'shines' like a faceted diamond. As the prey comes in for a closer look, it gets hypnotised and as they flounder, transfixed, the scorpionfish quickly gulps the prey down. The leaf scorpionfish can also mimic the colours of it surroundings - red, white, brown, and black.
Cardinalfish
Cardinalfishes are nocturnal creatures like the squirrelfishes. They feed on plankton and many species, like the squirrelfishes are reddish in colour to blend in with the grey night tones, which makes them almost invisible therefore they can go about foraging singly rather than in schools for protection. Like the Squirrelfishes, the Cardinalfishes have large eyes to capture as much light as possible in the dark. Their protruding eyes also warrant them a larger field of vision so they do not have to turn their bodies to change their angle of vision.
Cardinalfishes are one of the few fishes that incubate their eggs in their mouths. The eggs vary in size and egg clusters can range from a few dozen , sometimes into their thousands. The job of brooding is almost always for the male. The males get to incubate the eggs and in some species have the job of carrying their newly hatched fries around with them for as long as 2 weeks. In some species, the eggs are kept in the pharynx and sporadically turned and tossed about so that they are aerated.
The secretive Cardinalfish is difficult to spot in the day. They hide in algal patches, amongst the mangrove roots and have been found sheltering in sea anemones being careful not to touch the tentacles or in the spines of sea urchins or among sea stars and conches. The Cardinalfish is more wary of hiding in holes and caves, as these would also be places where its predators hide like the moray eel.
This golden coloured fish is active during the night. As it emerges from its hiding place at dusk, it warily remains on the bottom, checking out the scenes before heading off the to the open water, high above the bottom to feed on planktons. They are also often found on the bottom searching for tiny crustaceans.
This tiny fish has a distinct vertical bar right down the middle of it body. The front half of the body is painted gold and the back half is spluttered with dark brown polka dots. These fishes are seen sometimes during the day in small schools in rich coral areas, taking naps.
Goby
One time or another during our snorkelling sessions, we will get to see these tiny, coloured fishes. They are found quite often among coral rubble. There are many hundreds of species of Gobies in the Indo-Pacific reefs and estimated at 2000 species worldwide - probably many other species have not yet been identified. They are one of the most successful of fish families and are found living in tropical marine waters, in freshwater and in cooler temperate.
Some Gobies have even developed suck pads to cling onto corals and rock surfaces. As bottom dwellers, they have no need for swim bladders to make them buoyant as do other fishes and having swim bladders would, in fact be a disadvantage to them.
Gobies are generally small and species can range from 10mm to 20cm in length when adult. The Blueband Goby is one of the larger species in the family and lives among coral rubble about 20m-depth range. Many Gobies pair for life as it makes sense not to leave its safe haven to look for a mate. If they pair early on in life, they also save energy and time on looking for mates constantly.
The Goby excavates burrows in the sandy bottom, usually under rocks. It digs the burrow with its mouth and later the eggs are laid in it. Both parents guard the eggs until they hatch. Gobies are very territorial and will fend off enemy encroaching in their area.
Barracudas
Barracudas occur worldwide in tropical and warm temperate seas. They have a reputation almost as notorious as sharks and many divers descend with apprehension whenever they see these ferocious looking fishes lingering around. However, barracudas found in our waters are more wary of divers than we are of them.
Barracudas, like sharks are vital to the continuity of reef life. They are formidable predators, have slender bodies and powerful tails to home in on their kill in one full sweep. The Barracuda has a less advanced jaw mechanism. It is fused together in order to support the tightly packed sets of teeth. This mechanism makes it impossible for the fish to open its jaw wide to suck in its prey, therefore they snap their prey in two or more pieces instead, returning to pick up the pieces soon after.
Barracudas are attracted to shimmering objects, which they may think resemble their food so be careful not to wear jewellery. However, there have not been any known attacks in our region. The larger Barracudas tend to move around in singles as they may be older and grouping with other younger and faster barracudas may put them at a disadvantage when feeding. The smaller barracudas tend to wander about in schools of sometimes 100 or more individuals.
Some of the species found in our waters are the Chevron Barracudas, Blackfin Barracuda, Great Barracuda and Pickhandle Barracuda.
Rainbow Runner
This fish is elongated and has a yellow horizontal bar flanked by two blue horizontal stripes. The Rainbow Runner lives in schools and is commonly seen patrolling the outer reef slopes looking for wandering, defenceless fishes.
A good table fish, which has become an expensive fish commodity due to over fishing. This oval shaped fish is found in outer reef areas. The Juveniles live mainly in sandy coastal areas and estuaries, venturing out to the reefs when adulthood is reached
Bream
Breams are found up to a 20m depth range and are usually seen swimming close to the bottom on its own. Sometimes found in small groups, these fish are very active and sometimes seem to project sort of honeybee movements as one moment it is seen hovering and the next it darts off momentarily and returns to hovering. Most of its daylight hours are spent searching for benthic invertebrates and small fishes.
The Bream is also known as emperors. Breams have generally the same appearance as the Snapper and is seen on sandy fringes of the reef. It feeds on invertebrates and the Big-eye Bream have specialised 'molar-like' teeth at the back of its jaw, ideal for crushing tiny crustaceans and molluscs.
Goatfish
Goatfishes are easily recognised by the barbels found under their chins. These barbels are feelers and have taste buds, used to probe the sandy bottom for small invertebrates. It was observed in the Red Sea, a partnership was struck between a bird wrasse and a yellow goatfish. The wrasse would use its long snout to probe into crannies, sand and gravel with the help of the goatfish, which uses its sensitive barbels to scan for food. The other will eat food found and dug out by one. The partnership seems to work well!
Goatfishes are sometimes found schooling with other species of fishes that are of relatively the same size. They come together in under a common goal of safety in numbers.
Illustrations provided by Dennis Ho: Underwater photography by Moti Uttam
Corals & Fishes in Malaysia
