The scales on the lower flanks are mottled with blue, gold and yellow and there is a single black spot above the base of the pectoral fin.

The juveniles have series of elongated blotches on their flanks which merge as they nature to create a wide, dusky, mid-lateral stripe.

[3] This species occurs in coastal and inland freshwaters up to around 700 metres (2,300 ft) in altitude where it is normally found in upland streams with reasonable fats currents, even in rapids.

[3] The populations of Gobiomorphus coxii appear to be more abundant in the more southerly rivers in its range, it is especially numerous in flowing areas, even rapids..

Females lay eggs onto rocky surfaces which are the guarded and fanned by the male for several days until they hatch[2] into free-swimming larvae which are carried downstream.