TiggerFish

Triggerfishes are about 40 species of often brightly colored fishes of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pasifik. Most are found in relatively shallow, coastal habitats, especially at coral reefs, but a few, such as the aptly named oceanic tiggerfish (Canthidermis maculata), are pelagic While several species from this family are popular in the marine aquarium trade, they are often notoriously ill-tempered.

Anatomy and Appearance~

The largest member of the family, the stone tiggerfish (Pseudobalistes naufragium) reaches 1 metre (3.3 ft), but most species have a maximum length between 20 and 50 centimetres (7.9 and 20 in).
Triggerfish have an oval shaped, highly compressed body. The head is large, terminating in a small but strong- jawed mouth with teeth adapted for crushing shells. The eyes are small, set far back from the mouth, at the top of the head. The anterior dorsal fin is reduced to a set of three spines. The first spine is stout and by far the longest. All three are normally retracted into a groove. The ventral and the posterior dorsal fins are capable of undulating from side to side to provide slow speed movement. The sickle shaped caudal fin is used only to escape predators.

 

The two pelvic fins are overlaid by skin for most of their length and fused to form a single spine, terminated by very short rays, their only external evidence. Gill plates operculum too, although present are not visible, overlaid by the tough skin, covered with rough, rhomboid scales, that forms a stout armor on their body. The only gill opening is a vertical slit, directly above the pectoral fins. This peculiar covering of the gill plates is shared with other members of the Tetradontae order. Each jaw contains a row of four teeth on either side, while the upper jaw contains an additional set of six plate-like pharingeal teeth.
As a protection against predators, triggerfish can erect the first two dorsal spines: The first, (anterior) spine is locked in place by erection of the short second spine, and can be unlocked only by depressing the second, “trigger” spine, hence the family name “triggerfish”.
With the exception of a few species from the genus Xanthichthys, the sexes of all species in this family are similar in appearance.

Lagoon Tigerfish

Behavior~

The rather bizarre anatomy of the triggerfishes reflects their typical diet of slow-moving, bottom dwelling crustaceans, mollusks, sea urchins and other echinoderms, generally creatures with protective shells and spines. Many will also take small fishes and some, notably the members of the genus Melichthys, feed on algae. A few, for example the redtoothed triggerfish (Odonus niger), mainly feed on plankton. They are known to exhibit a level of intelligence that is unusual among fishes, and have the ability to learn from previous experiences.
 
Some triggerfish species can be quite aggressive when guarding their eggs. Both the picasso (Rhinecanthus aculeatus) and titan triggerfish (Balistoides viridescens) viciously defend their nests against intruders, including scuba divers and snorkelers. Their territory extends in a cone from the nest toward the surface, so swimming upwards can put a diver further into the fishes' territory; a horizontal swim away from the nest site is best when confronted by an angry triggerfish. Unlike the relatively small picasso triggerfish, the titan triggerfish poses a serious threat to inattentive divers due to its large size and powerful teeth.
Triggerfish are notorious bait stealers; rather than swallowing a bait whole, they nibble off small bites of it, making a small, stout hook essential to success in hooking them. Accordingly, the best baits are tough strips of fish skin, squid mantle etc.

Then you’re in for an extremely rewarding and entertaining experience, and only the size tank you can invest in limits your choice of Triggerfish. Keeping a single fish alone in a species tank is the only viable option for certain species, including B.undulatus, and V. vetula – the Undulated and Queen Triggers respectively. In fact, of the dream tanks that this author aspires to keep on day is a 120 gallon tank with a single, adult Undulates Trigger. For the B. Vetula, the 2’ Queen Triggerfish, it will have to be a tank in the 500 gallon range. Now the aquarist is only faced with the challenge of dealing with the highly destructive capabilities of these fishes, and nothing is safe! This means filters, powerheads, power cords and heaters! For this reason, these items are best kept in a sump, and out of the main tank. They are also adept, (and seemingly quite fond of), overturning and moving rocks and other pieces of décor. This tendency should be taken into account when aquascaping a tank that will eventually house and adult Triggerfish.
Speaking of things that should be kept out of the main tank, add your hands and arms to the list! As much as possible anyway, you should avoid inserting your hands into a tank containing a large Triggerfish – they can draw blood, and larger specimens (though unlikely to be found in your home tank) can remove fingers. The jaws of these fish are highly effective at what they are designed for, which is dismantling all manner of hardened items found in their environment. Always be aware of where your Triggerfish is when doing maintenance of your tank, even smaller specimens can deliver a painful and shocking bite.

Some Example~

Undulated Triggerfish (Balistapus undulatus)

As is the case with many families, a wide gamut of adult sizes, growth rates and temperaments makes generalizations difficult with regard to the minimum tank size. Further complicating the matter is the fact that even though a given species may attain say 14” in the wild, this doesn’t necessarily mean that such a size is realistic in captivity, even when kept in the largest home aquaria. Others are just tremendously slow growers, and are not likely to reach anything close to adult size even after 6 or 7 years of captive life. A good example of this is the genus Rhinecanthus, which comprises a few very popular species, including the Huma Huma Trigger (R. aculeatus) and the Rectangular Triggerfish (R. rectangulus). While fish of this genus are without a doubt some of the most easily kept and sociable of all trigger species, they are also very slow growers - annoyingly slow if truth be known. If you want a nice adult show specimen, you have a true exercise in patience ahead of you unless you purchase an individual that’s already in the 7 or 8” range. For this reason, a young specimen, say in the 2” range can be purchased and comfortably housed alone in a 40-gallon tank for at least 12 to 18 months before larger quarters are needed. Long term, 70 gallons will generally do since once they reach 5” or so, their growth slows down even more. The above can also be applied to the Undulatus Trigger (Balistapus undulates). The primary difference here is that an Undulatus MUST be kept alone, for they are without a doubt the most aggressive aquarium species available, either freshwater or marine!

Niger Trigger (Odonus niger)

 

 

A few commonly seen species get quite large, and grow at a much faster rate than our beloved Rhinecanthus species. Among these are the Niger Trigger (Odonus niger), the Queen Trigger (Balistes vetula), the Clown Trigger (Balistoides conspicillim) and the Blue Line Trigger (Psuedobalistes fuscus) All four are relatively fast growers and require very large tanks as adults. We’re talking 500 gallons plus for the Queen, and at least a 200-gallon tank for the remaining 3 species. Of the four, only O.niger generally makes a good tank mate over the long term when kept with other fish, while the enormous size and aggression displayed by the Queen Triggers makes long term cohabitation with other fish all but impossible. The Clown Trigger and Blue Line fall while quite aggressive, are still a bit more social that the Queen, and if acquired small can live quite comfortably in a 55 or 70 gallon tank for some time before a larger tank becomes necessary, and they will even coexist with other species for a time if enough space is provided. This almost always changes at some point though, so be warned! The Queen grows much too quickly to consider anything but a very large tank from the get go Having said all this, a tank of at least 70 to 80 gallons will provide sufficient space on a long term basis for the vast majority of Triggers that you’re likely to encounter at your local fish store if kept alone. Even with the more sociable species, you will be very limited as far as suitable companions unless even more space is afforded.

Clown Tiggerfish

Feeding~

The news couldn’t be better in this department – feeding a Triggerfish is the easiest thing you can imagine. Most species feed on hard shelled invertebrates in the wild, so they spend their day browsing the reef for crabs, shrimp, snails, etc. In captivity, they will accept a wide range of fresh and prepared fish foods, only leaving the aquarist the task of making sure that a variety of food items are offered, and that vitamin supplements are administered now and then to insure proper nutrition. Aside from a variety of appropriate foods that can be purchased in frozen form at most better fish stores, the aquarist can brows the seafood counter at his or her local grocer, and find many things that will have a Triggerfish eating out of the keepers hands in no time flat. A few of these items are fresh squid, octopus, scallops, fish, shrimp and crab. These foods can be cut into bite sized morsels and offered to the Trigger 2 or 3 times a day. Whole crayfish can even be offered, shell and all, and this will allow you to witness the business end of a Triggerfish doing what it was meant to do…demolish and consume! Even the few available species that are planktivores in the wild readily accept and thrive on all the options mentioned above with the exception of large, whole invertebrates.

One thing bears repeating here, and that is the importance of vitamin supplements. The primary reason for this is that feeding a predatory animal of any kind (be it bird, reptile, or fish) meat only does NOT replicate it’s natural diet in full. The predator in question is a consumer of whole animal items. When a Trigger consumes a crab in the wild, it not only ingests the meat, but all the blood, organs and other matter other that makes up the animal - not simply meat. Feeding a combination of whole food items and vitamin supplements mitigates any problems that my rear their head down the road due to improper nutrition, including but not limited to, poor color.

 

 

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