The forceps or longnose butterfly is a striking fish – the majority of the body is bright yellow, with the front being dark blue above the mouth and silver below. And the mouth consists of a very long snout, ending in a small mouth. In the hobby you are more likely to encounter the cousin of this fish, Forcipiger flavissimus
, also known as the longnose butterfly. The nose is shorter on the flavissimus
than on the longrostris
. Both species make excellent aquarium fish, and they are generally reef safe, although sometimes they mye graze a bit on corals, and actually eat tubeworms and the like.
The main problem in keeping this fish can easily be seen from looking at the mouth; it is very small, and the small mouth combined with the long snout tells you that this fish makes its living by poking into small spaces and eating the little things it finds there. The best setup for the longnose butterfly is in a tank where there is plenty of good live rock, with a thriving colony of small copepods and amphipods. This fish should be the only one feeding on them, so do not keep them with mandarins, or other butterflies. In the wild they are constantly feeding, and in the aquarium it is very important that you present them with food many times during the course of the day; they will accept any kind of meaty foods, as well as the frozen preparations specifically for fish like them. Once adapted to the tank they are usually good feeders, but it is important to watch them and make sure they are actively feeding.