The most common purple fish species is Zebrasoma santhurum, which is also known as the purple tang. This popular saltwater aquarium fish is native to the coral reefs of the Red Sea, the Arabian Sea, the Gulf of Aden and the waters off the coast of Sri Lanka.
Reaching up to 10 inches in length, this species is instantly identified by its bright blue to purple body and yellow tail. The body shape of the purple tang is similar to the sailfin tang, recognizable when the fish displays its fins in surprise, aggression or defense. The fish is also referred to as the yellowtail surgeonfish or the yellowtail tang.