Tropical Fish: The Thorn-Tailed Fish (Acanthuridae) is a family of forked-tailed fish, (aka: tang, surgeonfish, unicornfish & more). There are over 80 species in this family, all who have very sharp & dangerous spines on their tail, which fork out at their rear. Usually the spines lie flat against the sides of the fish but if they are angry or scared the spines stick out & can be used to lash out at any perceived threat as the fish thrashes its tail about.
