Description: bright greenish blue above, yellow on sides, with capability of flashing purple, chartreuse, and a wide range of other colors; body tapers sharply from head to tail; irregular blue or golden blotches scattered over sides; anterior profile of head on adult males is nearly vertical; head of females more sloping; the single dark dorsal fin extends from just behind the head to the tail; anal fin margin concave and extending from anus to tail.