What Is the Functional Adaptation of a Butterfly Fish?

By Lucas Wilkins

Many functional adaptations give the butterfly fish family a unique edge in the fight to survive and reproduce. The butterfly fish’s compact, mobile anatomy makes it adept at feeding off reefs. Its ornate, colorful design confuses predators and also makes it a popular addition to aquariums.

False Eye

The butterfly fish often has a dot on its dorsal fin that gives the impression that it’s "rear" is actually its “front,” fooling many predators into attacking from the wrong angle. This reef scavenger often has to reach into the back of the refrigerator, so to speak, by feeding in small alcoves that other fish can’t reach. This leaves its rear exposed, but the false-eye can give the impression that its rear end is actually the head of a much more dangerous eel.

Long Mouth

Much like an anteater or hummingbird, the butterfly fish has a long, tubular mouth that can retrieve food from hard-to-reach places.

Shape and Size

The flat shape of the butterfly fish allows it to swim into crevices that are too small for its predators. Unlike fish that swim long distances, the butterfly fish also has pectoral and pelvic fins that stick out like wings, allowing it to make sudden stops and sharp turns.


Safe and sound in an artifical habitat

poisson et aquarium image by Christophe Fouquin from Fotolia.com

Some people fear that the butterfly fish’s natural habitat is becoming endangered. Even if all the reefs in the world disappeared, however, the butterfly fish would live on in apartment and dentist office aquariums around the globe. In the end, the butterfly fish’s most enduring functional adaptation may be the inadvertent appeal it has to the world’s most powerful species, humans.