Though it is regularly seen in public aquariums, this fish is not commonly kept by aquarists. It is successfully kept by a good many nonetheless.
Seeing this fish in a local fish shop or anywhere else is an experience, the shape, the colours, it is really something. Anytime I see one anywhere I spend quite some time looking.
The fish is commonly known as the clown trigger and properly called Balistoides conspicilum. Why is it called ‘trigger’? This is because of the dorsal fin, for security the fish can go into a rock crevice and raise the dorsal fin, the second spine locks it in place. To release itself the fish exerts pressure on this second spine – the trigger – freeing the locking mechanism.
These fish are not suited to a reef aquarium as they could make a meal of mobile invertebrates and maybe some sessile invertebrates as well. As a snack, if the clown trigger can catch smaller fish it could eat them too. This would really please the aquarist! In addition, the fish could decide that the carefully placed reef rocks need re-arranging, again not an action that will endear it to the aquarist. Another reason is that the fish needs a lot of swimming space and in most reef systems the reef takes up a great deal of seawater volume.
So it is clear the fish is suited to the larger fish only system. Those with small and medium aquariums should not attempt to keep the fish as it could grow to 20 inches (circa 50.75cm). Many clown trigger fish being sold in stores are small, often only 3 or 4 inches, so growth must be allowed for. An aquarium of 100 gallons (circa 400 litres) net or larger is the size needed. This is a large system as the fish requires rocks that form caves so that it can find security, these rocks of course reduce net seawater gallonage. The rocks should be firmly positioned so that they will resist any attempted design changes. On the same theme, heaters that are in the display aquarium should have guards fitted; these are generally available and not expensive. In a fish only aquarium a sump is a definite advantage as first it provides an area where heaters can be placed out of harm’s way and secondly it increases the net gallonage of the system. It should be remembered though that when stocking is considered the seawater in the sump is ignored.
Stocking the aquarium needs care. The clown trigger is very territorial and will take exception to another trigger in their area (the aquarium!) and could do the same with other large fish. Designed for dealing with crabs and other prey with shells, the teeth of the fish give the impression that it is not for messing with. So the fish should only be kept with other large or larger very robust ones that are well able to take care of themselves. These other fish should be of a different colour and shape.
Clearly if the aquarist wishes to keep a fish only aquarium with a high number of varied fish types, the clown trigger is not a fish to choose.
When introducing fish to the aquarium for the first time the clown trigger should be the last one in, this creates the chance for all the fish to ‘accept’ each other. It is also very helpful if, on introduction, the clown trigger is smaller than all other fish present. On no account should the aquarium be overstocked.
An aquarist could introduce the fish and find that it is impeccably behaved and wonder what on earth all the cautions were about. Another aquarist could find the fish a total berserker! So it’s best to be prepared.
Feeding is easy as the fish will take just about anything on offer, though for a fish such as this brine shrimp and flake are a bit of an insult! Pieces of de-frozen fish, mussel meat, shrimp and the like are foods usually taken without problem. The fish is confident and can be fed from the fingers, but beware of those teeth, an aquarist can be forgiven for being nervous! It has been reported that hard shelled food should be given on occasion as this wears the teeth. The fish becomes quite tame and if movement is detected near the aquarium it will usually beg for food.
Over time the fish will be seen nearly all of the daytime hours in open water and becomes a real pet and a favourite. They are very hardy and long lived if attention is given to maintaining a high quality environment.
The aquarist who can provide a suitable environment for the clown trigger is lucky indeed.
The link is to some pictures and text: