El three-tailed fish this is a small fish, about 20 centimeters, quite compressed body and with large eyes. The operculum has three flat spines and the preopercle is finally serrated. There are between 36 and 39 scales, of a considerable size on the lateral line, which is complete and ends where the tail begins.
Except for the pectorals, all fins are large in relation to the body, since the dorsal fin has the third spiny radius greater than the rest, and the pelvic fins are very elongated, especially in males.
The tail contains very marked lobes, the lower one longer than the upper one. The color of the three tails is between pink and orange, and has three divergent yellow bands on each side of the head, the first one crosses the eye of the fish and the other two are below. In males, the tips of the pelvic fins are yellow, and they turn red when in heat.
The species of three-tailed fish lives on coral reefs, between 20 and more than 50 m deep, although occasionally it can be found at 200. It is grouped in banks of variable density. Closer to the surface it also inhabits caves or cavities of a certain entity. Its activity is greater during twilight than in the middle of the day. It feeds on zooplankton, epibenthic animals, and small fish.
It is a proterogynous hermaphrodite species. There seems to be a certain hierarchy among males, at least in the spawning season, when more or less ritualized fights between them are common. It reproduces in summer and the eggs are planktonic.