Groupers

Groupers are one of the main predators found in coral reefs. The larger groupers such as the coral grouper, the coronation grouper and the giant grouper are common in our coral reeafs. The shape of their body makes them awkward to swim with speed. Instead, they hide under table corals, behind sea fans and in holes…lying in wait for their food to swim by. The element of surprise attacks is their forte. Groupers prey mainly on fishes but have an appetite for eels, crabs and octopus. Being a predator that hunts best in the half-light hours of dawn and dusk, the octopus would have been taken at nightfall.

Groupers are largely solitary fishes except during spawning periods. But during normal occasions they move around the entire reef on their own. The larger species do not have to defend their holes or territories aggressively as there are plenty holes or table corals, which they can move to. Even if these hiding places are already occupied, the present occupants will have no choice but to vacate for them...as size does really matter in the realm of the reef.

This grouper is one of the more colourful specie, red all over and spotted blue.

Also known as rock cods in Australia, it is most often seen in clear waters of outer reefs to a depth of about 150m. It feeds mainly in the morning and mid afternoon preferring Anthias, other small fishes and crustaceans.

This beautifully painted grouper is usually found in outer reefs from shallow reef areas to waters of 240m deep. It feeds mainly on fishes but do not mind a variety in their diet sometimes feeding on crustaceans. This fish has been associated with a number of Ciguatera poisoning and one should be extremely careful if served with this fish at dinner dates although it has been mentioned that some farming has been introduced in certain areas where they are reared for commercial use.

This fish is recognised by its sickle-shaped, yellow-edged tail and its distinct patterns and colouration.

This is the largest specie in the grouper family it can grow up to 2.5m long and weigh 400kg! This fish has the honour of being the largest of all bony fishes living on coral reefs. The Giant Grouper is extremely curious of divers and have a habit of turning up unexpectedly behind you. It will watch from a safe distance or tag along for the show until it tires of it.

Anthias

The sub-family, Anthiinae of the grouper family is completely different in appearance from its larger relatives. There are 100 members in this sub-family and they are mostly delicate, brightly painted, swimming in groups just above the bottom & mid waters.

The Square-blotched Anthias hovers around the outer reef slopes, usually below depths of 15 to 20m and prefers areas where there are sporadic currents. These currents bring in fresh batches of zooplankton, their source of food.

Also found in the outer reef in aggregations, the Flame Anthias feed on zooplanktons brought in by the currents. When threatened, it flees into the rocky crevices nearby. Its social structure and behaviour is the same as the Square-blotched Anthias . When courting, the male's colour intensifies and the red dorsal fin is in its erect position. If the male is removed from the group, the dominant female - the highest in the female rank and hierarchy takes on the position of the male and in several days would metamorphosis completely into a terminal or supermale

 

Sweetlips

There are 12 species of Sweetlips in South East Asia. Another 2 Sweetlips species found in these waters are the Many-spotted or Harlequin Sweetlips (Plectorhinchus chaetodontoides) and Lined Sweetlips (Pletorhynchus lineatus). The Sweetlips are medium-sized, snapper-like fishes found usually wandering on their own around the reefs. These fishes have thick lips and are strikingly coloured with distinct patterns running the length of their bodies. They feed actively at night on invertebrates especially crustaceans and are sometimes found around wrecks and coral valleys catching up on their 40 winks during the day. They form groups in such circumstances as a form of defence.

Young Sweetlips have very different coloration from the adults. The juvenile Oriental Sweetlips is dark brown and has a white snout and breast. A pair of diagonal white bands stretches across its tail and there are 2 white saddles along the back. This is indeed very different from the adult, as shown in our illustration below.

Fusiliers

The Blue and Gold Fusilier is very common in our reefs. There are about 20species and they usually hang around in the outer reef slopes and in areas where there are sporadic strong currents. The body is generally bluish in colour, is tapered and cylindrical and ends with a forked bright yellow caudal tail. Safety in numbers for these fishes are important as this sort of schooling behaviour is adopted to confuse predators. With this method, the predator is less likely able to target on a single prey. The more fishes in the group, the less chances of a successful kill. Divers may sometimes experience the Fusiliers' 'swarming behaviour. These schools often engulf divers in their swirling vortex for a time before swimming off.

Puffers

Puffers are my favourite of all fish species in the reef. The most evolved creature in the sea, this odd shaped fish moves slowly around the reef on its own, stopping to pick at algae, molluscs, crustaceans, worms and sponges. They are curious little creatures but at the same time can never resist a snoop around unfamiliar objects and intruders, always keeping at a safe distance when investigating the scene.

The Pufferfish moves awkwardly slow. Watching it swim away, one may have the feeling that this fish is a miniature model of the submarine mentioned in the book '20,000 leagues under the sea' by Jules Verne. Since it doesn't move swiftly, it has to arm itself with body armour or the secretion of toxic substances for protection. And because it is so well armoured, it has difficulty moving its tail. Constantly in motion, the Pufferfish derives its propulsive force from its tiny pectoral, dorsal and anal fins which flutters like a bumblebee's. This enables the Pufferfish the agility to hover, reverse and stop short. Sometimes, as the Pufferfish swims away, the observer can hear stridulating, that is, scraping sounds emitted by the fish.
Many fishes have highly developed scent sensory. However, Pufferfish have
no nasal sacs and therefore has to depend more on vision.

The pufferfish, as opposed to popular belief, cannot puff up into a balloon everytime it is frightened. Sometimes this puffing creates so much trauma to the puffer, it dies in the process. Divers often have a habit of shaking the puffer by its tail but in doing so, it shortens the life of the puffer.

Often found feeding on corals, algae and small crustaceans around coral patches, the black-spotted Pufferfish is easy to spot. It putters around on its own time but is vary of unfamiliar images. Once confronted by predators or enemies, it swallows large amounts of water to help inflate its body many times its original size. This form of defence either allows it to wedge itself in crevices thus making them difficult to dislodge or makes it impossible for the predator to swallow. Plus, the Pufferfish has a powerful deterrent to its enemies..it produces a potent poison in its tissues, mainly the liver and ovaries. Even so, the Pufferfish flesh is highly sought after in top-notched restaurants in Japan. The flesh is detoxified and must be prepared by experienced chefs who specialise and are licensed to prepare such delicacies. But there have been many cases of Pufferfish poisoning resulting in deaths. A palatable dish but with a heavy price to pay unless prepared with great care and skill. The Black-spotted Puffer can change colours to suit its background, from a dull brown to bright yellow.

There are 10 known species found in South East Asia. This tiny Pufferfish have limited ability in inflating unlike other puffers and commonly seen in pairs rather than solitary, on reefs, sand flats and wreckage. The Sharpnose used to belong to a separate group but have now been included in the puffer family. The smallest of all puffers, the Sharpnose puffer differs from other puffers in the shape of its head.

It is an omnivore and has a good appetite for algae, crabs, brittle stars, sea urchins, sea squirts, coral polyps, sponges and worms. Like other puffers, the Sharpnose also produce powerful toxins, which if eaten can cause severe poisoning and even death in humans. In addition to that, the Sharpnose Puffer also produces a skin toxin. Because of its reputation, this puffer has an almost identical fish that mimics its pattern and colours. The mimic filefish is almost exactly like the Black Saddled Toby. One has to look extremely closely at the lines on its snout to tell one from the other. The Toby has horizontal lines on its snout whereas the mimic has vertical lines.

When the little Sharpnose retires for the night, it 'dresses' down to conceal itself from potential predators. The bars on its snout and tail disappear, its eyemarkings and the bright spots fade away. And when the sun rises, it dons its colourful bars and stripes to meet a new day.

Another distinct Pufferfish that roams around the sheltered reefs and near lagoons, the Map Puffer has beautiful patterns painted all over its body. The radial streak patterns camouflage its eyes and dark disjointed streaks run from the mouth to the caudal fin.

 

The Freckled Porcupinefish is found in tropical reefs worldwide and is a close relative of the puffer. Like the puffers, the Porcupinefish can inflate its body several times its original size by swallowing large quantities of water (or air if it is on land). Like the porcupines, the Porcupinefish have spines that cover its entire body. In some Porcupinefish species, these spines can be erected, in others..they are short and thorny. With such tools, the Porcupinefish has few predators except for sharks, jacks and barracudas.

The Porcupinefish has fused teeth that are used to crunch on its favourite food such as the sea urchins, crabs, and molluscs.

Others found in our waters are the yellow-spotted burrfish(Ciclichthys spilostylus) and the black blotched porcupinefish(Diodon liturosus)

Often divers and sometimes snorkellers come across these cute little fishes. In its juvenile form, the yellow Boxfish are dipped in yellow and splattered with black spots. As it grows, the fish gradually turns brown and loses its spots. When adult, the body is of purplish brown. The Boxfish is unique as a fish species in that the body is encased in a bony carapace. With such restrictions, movement is also compromised. The Boxfish are often seen 'putt-putting away' by propelling itself with a sculling movement of the dorsal and anal fins.

Boxfish, like the puffers, have a coat of armour to protect them from predators and some species produce a skin toxin that can be lethal and is released when the fish is under stress. Although they may look harmless, the consequence of fondling such a creature may be dire!

If you think the yellow Boxfish is peculiar, the Longhorn Cowfish is in its own league of bizarre looking fishes. It has a polygonal body and like the Boxfish it has a bony carapace underneath which gives its shape and protects it like a shield. The eyes are protected by two large spiny protrusions from its head. It feeds on invertebrates found on the bottom and is skilful at removing the camouflaging layer of sediment to reveal the crabs, molluscs and other crustaceans concealed.

Illustrations provided by Dennis Ho: Underwater photography by Moti Uttam

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