Appearance
The rock goby is usually black with white blotches, but they can change color, and males are much more black when guarding the eggs. The neck area lacks scales and there is a pale band on the top of the first dorsal fin. Both dorsal fins lack black spots on their leading edges. This species can reach a length of 12 centimetres (4.7 in) TL and has been known to live for ten years.

