The Forktail Blenny, also known as the Lyretail Fang Blenny or Yellowtail Fang Blenny, has a caudal fin that resembles a fork, with two long exterior spines and five much shorter middle spines. The body is a pale blue that runs like watercolor into a bluish-yellow at the tail. Males are generally larger than females and experience a succession of color changes when breeding.
The Forktail Blenny needs a minimum tank of 30 gallons with live rock for hunting and grazing. It is best to keep only one per tank unless a breeding pair is maintained. The Forktail Blenny is considered venomous and should be kept only with caution around children having tank access since it may perceive fingers as an attacker and deliver a similarly painful bite.
The diet should consist of finely chopped crustacean flesh, mysis and vitamin-enriched brine shrimp, as well as frozen herbivore preparations.
Source: Live Aquaria. Photo used as reference.