Doctorfish is a tropical fish found in the Atlantic Ocean. It is grayish-brown to dark brown and has 10 to 12 vertical markings on its sides. Its fins are blue to gray. The doctorfish belongs to a group of fish called surgeonfish. Like other surgeonfish, it has a sharp, scalpel-shaped spine that folds into a groove on each side of the body near the tail. The spine can be raised out of the groove and used to slash at attacking fish.