Prionobutis microps
Crazy Fish (also Microps)
Species Summary
Confined to the Australia–New Guinea region and growing to about 23 cm, Prionobutis microps is a cryptically coloured dark brown gudgeon with faint markings, rounded fins and noticeably large pectoral fins banded with thin dark stripes. Around Darwin it is known from the Adelaide River, Rapid Creek and other nearby waters, typically inhabiting estuaries at the brackish–freshwater interface, where it shelters in rock crevices and under logs and preys on worms, fish and shrimp.
Breeding
A captive pair of Prionobutis microps roughly 12 cm long, conditioned on live blackworm, spawned with the typical gudgeon courtship display of body-wagging and fin-flaring, laying several thousand eggs on the roof of a PVC-pipe cave in water of pH 7.7, conductivity 3,500 µS, carbonate hardness 100 ppm and 28.5 °C. The eggs hatched within 60 hours, and the free-swimming fry adopted an unusual vertical, surface-facing posture, swimming in repeated up-and-down cycles; being too small to feed successfully at that stage, none survived long.
Remarks
The name “Crazy Fish” is shared with an unrelated species, Butis butis, and its origin is best illustrated by an angler’s tale from the Territory: a four-foot Threadfin Salmon caught in the lower Adelaide River, once gutted, was found to have an intact 7–8 inch Prionobutis microps still alive inside its stomach — bleached white by digestive fluids and missing some fin material, but alive nonetheless. Nursed back to full health, it went on to live for about another year in captivity before eventually jumping from its tank.
Compiled for Home of the Rainbowfish from ANGFA sources: G. Briggs, “A crazy name for a ‘crazy fish’”, Fishes of Sahul 14, 2000, pp. 666–668.