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 behind
the head to the tail; anal fin margin concave and extending
from anus to tail.