Yellowtail is a thin-bodied, right-eyed flounder. They are wide, nearly half as broad as they are long, with an oval body. They have a small mouth and an arched lateral line. Their eyed side, including the fins, is brownish or olive, tinged with red and marked with large, irregular rusty red spots. True to their name, their tail fin and the edges of the two long fins are yellow. The blind side is white, except for the caudal peduncle (the area between the body and the tail), which is yellowish.