Acnodon normani · Sheep Pacu

Overview

The Brazilian serrasalmid Acnodon normani is sold under sheep-pacu and tiger-pacu names. Its tendency to pick scales from larger fish makes compatibility a more important consideration than its frequent reputation as a plant eater.

Distribution & habitat

Records concern the lower Amazon region, possibly restricted to the Xingu and Tocantins watersheds. The type site is the Santa Teresa, a western tributary of the upper Tocantins in Goiás, Brazil.

The Sono River habitat contains clear water crossing savanna rather than surrounding forest. A heavily stained forest-stream setting should therefore not be assumed for every locality.

Aquarium setup

Allow at least roughly 150 × 45 cm of floor space. Provide some cover, good oxygenation, and a degree of circulation. Layout is otherwise relatively flexible. Living plants may be eaten.

Diet & feeding

Fruit eating or general herbivory is often attributed to it, but captive observations also suggest consumption of fish scales. Feeding is usually straightforward, with sinking prepared foods and frozen items readily accepted. A herbivore label should not obscure its potential to damage companions.

Behaviour & compatibility

A conventional community is unsuitable because larger fishes may be picked at. Much smaller species appear less frequently targeted, without establishing reliable long-term compatibility. A conspecific group is possible when enough space is supplied.

Sexual dimorphism

Larger adult males develop a distinct anal-fin lobe. This is a mature-male feature rather than a reliable guide for every young fish.

Notes

The similar Acnodon setnai has a slimmer body and enlarged lower lips. Trade names alone do not reliably separate such look-alikes; origin and morphology should be considered together.