Scientific name:
Melichthys niger
Distinctive features:
1. Black body
2. Rounded football shape with rounded dorsal and anal fins opposite each other
3. Thin, iridescent blue lines at base of dorsal and anal fin
4. Tail curves inward
5. Usually swims up in water column, where it appears as a silhouette to the diver
Size:
Up to 12" (30cm)