Mogurnda mogurnda

(Richardson, 1844)

Northern Purple-Spotted Gudgeon

Species Summary

Mogurnda mogurnda ranges from the Ord River in the Kimberley across the Northern Territory, around the Gulf of Carpentaria and down the eastern side of Cape York to the Mossman River, where it gives way to the closely related southern species, Mogurnda adspersa — though the exact boundary between the two, and whether some intermediate populations represent hybrids or misidentifications, remains genuinely unclear in places. It also occurs in New Guinea, from the lower Kikori River west to Etna Bay. The body is brown dorsally, mauve on the sides and whitish on the belly, with 3–4 diagonal reddish cheek stripes, numerous red or cream spots, and yellow-margined dorsal fins carrying rows of red spots; it grows to around 12 cm standard length. Of all Australian Mogurnda, this species shows the widest range of meristic variation, and it is genuinely possible that more than one species is currently lumped under this name.

Distribution & Habitat

Habitat use is correspondingly broad: billabongs, swamps, lakes, reservoirs, drainage ditches and clear flowing streams, in both dense vegetation and rocky pools with little plant cover at all.

Breeding

A first-hand tank-breeding account illustrates both the rewards and the frustrations of breeding this species: repeated intraspecific aggression forced the keeper to separate and re-pair fish several times before a first successful spawning, on a piece of shale angled at 45 degrees. Two batches were compared directly — one where the eggs were moved to a separate hatching tank once eyespots became visible, and one left in place with the guarding male. The moved eggs hatched a day earlier but produced weaker fry, suggesting the move triggered a premature hatch; the batch left with the male hatched later but produced noticeably stronger fry. A hard lesson was learned about food: the first attempt lost its entire hatch to a lack of suitably sized live food, since a microworm culture takes time to establish and must be ready before the eggs hatch, not started afterwards. Mogurnda mogurnda does not appear to be as broadly omnivorous as rainbowfish or Empire Gudgeons, and generally refuses flake food.

Compiled for Home of the Rainbowfish from ANGFA sources: M. Young, “A tank breeding of Mogurnda mogurnda”, Fishes of Sahul 4, 1987, pp. 174–177; Anonymous, “Mogurnda mogurnda (Richardson 1844) Common Name: Northern Purplespotted Gudgeon”, In-Stream 20, 2011, p. 16.