Pseudaphritis urvillii


Pseudaphritis urvillii is the only species of fish in the family Pseudaphritidae and the genus Pseudaphritis. It is known also as the congolli, freshwater flathead, marble fish, marbled flathead, sand trout, sanding, sandy, sandy whiting or tupong. It was initially classified as a member of the family Bovichtidae.

Etymology

The genus name "pseudaphritis" is from the Greek: pseudes, meaning "false", -idos meaning anchovy, and aphritis, derived from aphrioeis meaning "foam".

Distribution and habitat

The congolli is found in fresh, brackish and marine waters around south-eastern Australia, including Tasmania, and is endemic to Australia. It lives mostly in slow-moving waters of estuaries, rivers and streams. Water temperatures in its habitat range from. This fish will inhabit areas with log snags, overhanging banks, and leaf litter.
Between late April and August, it migrates south to estuaries and sea to breed.
In 2017, congolli were recorded in five rivers on Kangaroo Island in South Australia for the first time, thanks to a project conducted by Department of Environment, Water and Natural Resources and carried out by a number of citizen science volunteers.

Description

The congolli is a slender, mottled fish, with a silvery-white underside. Its head is slightly flattened, with eyes positioned towards the top and the snout is pointed. It has two separate dorsal fins. The colour varies according to where it lives: it may be bluish, purplish or reddish-brown, marbled with greenish-brown above, and a yellowish white to silvery colour below. Juvenile fish have black saddles on their dorsal surfaces.
The largest adult measured is about long. Usually, adults grow up to long.

Diet

The congolli is a carnivorous ambush predator, and feeds on insects, fish, crustaceans, worms, molluscs, and other invertebrates.

Behaviour

The congolli is an ambush predator that usually buries itself in the substrate.

Reproduction

Congolli are catadromousthey live in freshwater habitats as adults, and migrate downstream to estuaries to spawn. Adults migrate south to estuaries reproduce between late April and August. The larvae are carried out to sea, and slowly move upstream as they grow; the larger adults live furthest upstream.

Importance to humans

living in the area used to eat Congolli, and the flesh is today considered "excellent eating". However the fish are rarely large enough and no longer important in commercial fishing, although once a minor part of lower Murray fisheries.