If you are looking for a truly spectacular fish that can be as personable as a puppy and as unpredictable as a bull shark, then send in the clown—the clown triggerfish (Balistoides conspicillum), that is! The clown triggerfish is one of the most striking fish on the coral reef, but it is also a threat to a variety of fish and invertebrates.
Difficulty: The adult clown triggerfish is usually a pretty durable aquarium species. However, small juvenile clown triggerfish often have a difficult time acclimating to captivity, as can larger adult clown triggerfish (larger than 12 inches in length). Frequent feeding is essential to keep young clown triggerfish fat and “happy.” This means adding food to the aquarium at least three times a day. Feed your clown triggerfish a varied diet that includes chopped frozen seafood, frozen preparations for herbivores, frozen mysids and frozen krill. These should be eaten with gusto! Adult clown triggerfish should be fed a similar diet. You may want to include live mussels that are available at some bait shops or fresh seafood providers. The clown triggerfish will use its strong teeth and jaws to break up the shells and get to the tasty morsels inside.
Physical description: The clown triggerfish is truly a memorable fish. The adult clown triggerfish is black overall, with big white spots on the belly and a reticulate pattern of yellow lines on the back. Clown triggerfish also have orange “lipstick” with yellow highlights on the anal fin, dorsal fin and caudal peduncle. Juvenile clown triggerfish have a black body, and the whole body is covered with white spots. The clown triggerfish reaches a maximum length of almost 20 inches. There is really no other triggerfish that looks like the clown triggerfish.
Range: The clown triggerfish ranges from east Africa east to Samoa and the Line Islands. It is found on lagoon patch reefs, reef faces and slopes at depths of 10 to 240 feet. Young B. conspicillum are found at greater depths than the adults and are most often seen hanging out near reef walls. When threatened, this fish will dive into a hole or crevice and raise its trigger spine so that it cannot be extracted.
Compatibility: While a juvenile B. conspicillum can be kept in a community aquarium with more passive fish species, it will turn into a potentially murderous tankmate as it grows larger. I have seen and heard stories about large adult clown triggerfish that ignored fish neighbors in a larger aquarium for months or even years, and then, as if someone flipped a switch, the clown triggerfish goes crazy and starts tearing up the other fish. There are other individuals that seem to maintain a more stable demeanor and don’t become overly aggressive. Belligerent fish are the only suitable tankmates for most adult clown triggerfish. Species that are best-suited to live with a clown triggerfish include large groupers, dampiera dottybacks (Labracinus spp.), larger Maori wrasses (Cheilinus spp.), mean surgeonfish (e.g., sohal surgeonfish, Acanthurus shoal; lined surgeonfish, A. lineatus) and other aggressive triggerfish (e.g., orangelined triggerfish, Balistapus undulates). If you are lucky enough to get a clown triggerfish that is less of a sociopath, you may get away with large angelfish, various surgeonfish and rabbitfish. Keep only one clown triggerfish per aquarium. While clown clown triggerfish are not a good choice for most reef aquariums, as they feed on a wide range of invertebrates (including crustaceans, mollusks, sea stars and urchins), I have seen them in reef aquariums that were comprised mainly of soft corals. Some triggerfish will also bite the tips off of staghorn corals (Acropora spp.).
Aquarium conditions: The young clown triggerfish can be housed in an aquarium as small as 10 gallons. But it will outgrow an aquarium of this size quickly. If kept on its own, an adult clown triggerfish can live its entire life in an aquarium as small as 75 gallons, but if you want to house it with other fish, an aquarium of at least 180 gallons is best. One way to keep your clown triggerfish entertained is to place a lot of rubble on the aquarium bottom and add a handful of live ghost shrimp for the clown triggerfish to hunt. The clown triggerfish will lift chunks of rubble in its mouth as it tries to uncover concealed prey. The clown triggerfish will also use its power jaws to lift and move faux corals. The water parameters for the clown triggerfish should be a pH of 8.1 to 8.4, a specific gravity of 1.019 to 1.025 and a water temperature of 74 to 82 degrees.
Care considerations: The clown triggerfish has been known to attack its owner. I know of several incidences in which aquarists have ended up with stitches and scars as a result of clown triggerfish attacking their hand or arm as they rearranged the decor or cleaned the aquarium glass.
Breeding: The clown triggerfish is not likely to spawn in the home aquarium.