By Brendan Ebner
In my experience the Scaleless goby attains a maximum total length of about 50 mm. It lives in coastal streams of the Wet Tropics in flowing water (typically 0.2-0.4 ms-1, Donaldson et al. 2013) often in laminar surface flow (Pusey et al. 2004) in very specific habitat. Snorkelling is a great way to appreciate colonies of this goby in shallow runs. By moving your hands slowly over the benthos, individuals will spook from subsurface haunts and interstitial spaces. If you approach the run very slowly from the downstream side and wait patiently, individuals will sometimes swim by and interact with one another, seemingly without being scared of the massive snorkeler. On some occasions the sands will literally shift to reveal the once buried goby as if by a magician’s sleight of hand. The Scaleless goby can re-bury just as quickly or dart off for a distance of up to a couple of metres with a startling bound of acceleration resembling that of a Mexican jumping bean. The female is somewhat drab and has a smaller head and mouth than the male. The male is cloaked in a skin that defies accurate description. But here goes nothing. It is orange in places, intermixed with green and white camouflage patches. There is a smattering of light blue-whitish fluorescent spots over much of the body. It is also somewhat bug-eyed, and has a distinctive scissor shaped pattern on the caudal peduncle. The male opens an enlarged grotto of a mouth, revealing a bright orange gob that serves as a signal to neighbouring ladies (see photo). They make fascinating pets but do best in a small aquarium with at least two power heads to create benthic turbulence, and require daily feeding to maintain body condition. There is still much to learn about the Scaleless goby, which has several similarly poorly known congeners found in streams of the tropical Pacific (e.g. Keith et al. 2013).
Donaldson, J. A., Ebner, B. C. & Fulton, C. J. (2013). Flow velocity underpins microhabitat selectivity in amphidromous gobies of the Australian Wet Tropics. Freshwater Biology 58, 1038–1051.
Keith P., Marquet G., Gerbeaux, P., Vigneux, E. Lord, C. (2013). Poissons et crustacés d’eau douce de Polynésie. Taxonomie, écologie, biologie et gestion. Société Franchcaise d’ Ichyologie, Paris. 282 pages.
Pusey B. J., Kennard M. J. & Arthington A. H. (2004). Freshwater Fishes of North-EasternAustralia. CSIRO Publishing, Melbourne, 702 pp.