The Cocos Frillgoby is a small fish that superficially resembles a number of similar goby species.
Fishes in the genera Bathygobius can be easily confused with those of Istigobius. The main difference is the overhanging snout in Istigobius. Bathygobius has larger elongate dark spots on the midside and numerous small white spots (Istigobius has white lines, but no spots). Istigobius tends to have brighter colours, with Bathygobius being black, brown and white.
The species can be found in a range of bethic habitats from coral reef to rocky reef.
The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Click on the map for detailed information. Source: Atlas of Living Australia.
Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.