The surgeonfish family includes some of the most exquisitely patterned and colored of all reef fishes. But one feature that is common to all is that they all have one or two pairs of scalpel-like blades on the Sides of their tails. These give the family its name and can inflict serious cuts if the fish are handled carelessly.
The orangespine unicornfish (Naso lituratus) with its bright orange spots warning of its spines; the hepatus tang (Paracanthurus hepatus) with its electric blue and black body, and the clown surgeonfish (Acanihurus lineatus), oraiige-and-blue striped, are just a few examples.
Moorish idol and Rabbit-fishes. The Moorish idol (Zanclus cornutus) and the rabbitfishes (Siganus) are close relatives of the surgeoniishes. The Moorish idol is for many people the quintessential reef fish; with its bright, contrasting yellow, white and black color, prominent snout, and long, thin dorsal fin, it is indeed an elegant-looking animal. They are fairly common grazers, and can be found all the way from the east coast of Africa to the west coast of Central America.
The rabbitfishes look much like surgeonfish or Moorish idols, although with the exception of the foxface (Siganus volpinus) and the coral rabbitfish (S. corallinus), not as brightly colored. They have no "scalpels," but they do have a strong venom in the short spines of their fins, and should not be handled.
Tuna and Mackerels. Although one or two members of the family Scombridae patrol reefs—particularly the dogtooth tuna (Gymnosarda unicolor)— most are true pelagics, living in the open sea, and will only occasionally be seen on the outer reef edge. When traveling by boat between islands or to offshore dive sites it is not unusual to see big schools of tuna splashing at the surface, often with attendant flocks of seabirds overhead. These schools are usually composed of slapjack tuna, although there are several other species found in Indonesia.
A school of pyramid butterfly-fishes, Hemitaurichthys polylepsis. These plankton feeders gather in large groups around the lip of drop-off reefs in eastern Indonesia. The Bunaken group, Sulawesi,
Indonesian flashlight fishes, Anomalops katoptron, top, is the more common of the two. Photoblepheron palpebratus tends to be found in smaller groups in rather deep caves, Both species are easy to see in TuIamben Ban: Anomalops on the wreck, and Photoblepheran on the wall. Both grow to about 10 centimeters long.
Skipjack (Katsu won is pelam is) grow to just under a meter in length, and are plump and streamlined, with a characteristic series of about five black lines on their bellies. They will not be seen on the reef itself, however, although there will be plenty In the fish market.
Triggerfish. Triggers (family Balistidae) are common fish at moderate depths on the reefs, where they hunt spiny crustaceans and echinoderms. Shaped like a compressed football and often exquisitely marked, they use powerful jaws to dispatch their hard-shelled prey. Large schools of the black triggerfish (Odonus niger), which is actually more blue in color, can be seen hovering off the reef walls, swimming with characteristic undulations of their fins. This fish is sometimes called the red-toothed trigger, although you have to look very closely to see that its teeth are, indeed, red.
Some distinctively marked triggers include the Picasso trigger (Rhinecanthus aculeatus), so-named for its cubist markings, and the undulate trigger (Pseudo-balistes fuscus), covered with wavy markings. The largest trigger you will see on the Indonesian reefs is the Titan triggerfish (Balistoides viridescens), a loopy-eyed and sometimes aggressive animal that grows to more than 60 centimeters.
The most dramatic of the family is the clown triggerfish (Balistoides conspicullum), with its bright orange snout, blue body, and white-spotted belly. The clown trigger is very territorial, and will patrol the same area of reef. When threatened, a clown trigger will wedge its body head-first into a crack in the coral wall, and extend its dorsal spine. The first spine, once raised, is locked in place by the second, making it impossible to pull the fish out of his hole. A diver who knows what he is doing can reach in and gently push back the second spine, unlocking the fin. He can then extract the irritated fish.
Puffers. The curious puffer-fishes (family Tetraodontidae) are solitary omnivores, often seen wandering about the reef in their slow, almost clumsy way and plucking at algae, crustaceans, molluscs, worms and sponges. When threatened they inflate themselves with large quantities of water, which either locks them into a coral crevice, or makes it impossible for a predator to swallow them. In addition to this protection, the skin and most of the internal organs of puffers contain a deadly poison. This poison is absent from the flesh, which in Japan is the highly prized fugu.
A common putter on Indonesian reefs is the dog-faced or black-spotted puffer (Arothron nigropunctatus), which exhibits a great deal of color variability, from the usual dull brown to bright yellow; always with many small black spots.
The related porcupinefishes (family Diodontidae) possess the same defenses as the puffers, with the addition of numerous spines, which become erect when the animal is inflated. The common porcupinefish (Diodon hystrix) is often seen. Boxfishes (family Ostraciontidae) are similar to puffers, except their protection comes in the form of a hard, roughly cubical external covering.
Nocturnal fish. At night the schools of clay active species break up and the fish take refuge In holes in the reef. They are replaced by nocturnal species such as the cardinalfishes (family Apogonidae), bigeyes (family Priacanthidae), and squirrelfishes or soldierfishes (family Holocentridae), which feast on the abundant night plankton.
One of the most interesting families of fish to come out at night are the flashlight fishes (family Anomalopidae). These delightful littleblack fish have special organs under their eyes which contain million of light-producing bacteria. The fish are able to cover and uncover these organs to produce characteristic flashes of blue-green light. The function of these lights is not fully undertood but they are probably udrd to communicate, to see by, and perhaps to confuse predators,
Two species of flashlight fish are found in Indonesia. The most often seen is Anomalops kataptron, a 6-8 centimeter fish that forages for plankton in shallow reef waters, often in large schools. (Anomalops also occurs in a much larger—27 centimeters—deepwater form that lives in up to 400 meters of water.) Photoblepharon palpebratus is rare and tends to occur in relatively small groups in deep caves.
Marine Reptiles
Sea turtles. One of the most delightful experiences a diver can have swimming with turtles, and in Indonesia such encounters are quite common. Six species of marine turtles are found in Indonesian waters, but the two most likely to be seen by divers are the tiawksbill turtle (Eretmochelys imbricata and the green turtle Chelonia mydas).
They are not always easy to distinguish underwater, althoug the hawksbill has a distinct beak and the trailing edge of its shell is jagged. The hawksbill is also generally smaller, and is tortoiseshell brown (instead of olive green) although such relatively minor color difference are very hard to determine underwater. A third species that may be seen by divers is the loggerhead (Caretta caretta), which is much like the green turtle, except it has a massive head.
The green turtle feeds almost entirely on sea grass, while the hawksbill and loggerhead are both largely carnivorous. The shell of the hawksbill is covered with large horn-like scales, the source of "tortoiseshell." Tortois shell products—and even stuffed and varnished hawksbill turtles—are offered in Indonesian markets, although import into most Western countries is strictly prohibited.
A bluestreak cleaner