红点魮脂鲤 · Bleeding Heart Tetra

Overview

A conspicuous red shoulder mark places Megalamphodus erythrostigma among the similar bleeding-heart tetras. It is generally peaceful, although mature males display territorial behavior. A suitable group, adequate room, and a mature, clean aquarium support its best condition.

Distribution & habitat

The species comes from the upper Amazon around the Brazil–Peru–Colombia frontier, extending from the Purus at least upstream to the Nanay near Iquitos and into some Colombian tributaries.

Sluggish tributaries, side channels, and forest lakes provide roots, fallen wood, overhanging plants, and aquatic vegetation. Water is often soft, weakly buffered, and brown, though turbid white-water lake records show that habitat is not restricted to one water color.

Aquarium setup

Use a footprint of at least roughly 90 × 30 cm. Plants and a dark substrate enhance coloration, while sand, roots, and branches create shade. Leaves support microorganisms useful to fry. Subdued lighting and floating vegetation are appropriate.

Organic pollution is poorly tolerated. Introduce fish only after filtration is biologically mature and make weekly water changes routine.

Diet & feeding

This opportunistic omnivore shows striking variation between localities: some lake fish consume mostly fruit, whereas stream fish feed heavily on aquatic insects and larvae alongside plant fragments.

Captive fish readily accept food. Combine live or frozen bloodworms, Daphnia, and Artemia with quality flakes and granules, including some plant- or algae-rich products. Fresh fruit pieces can also be grazed when submerged, but remove them after only a few hours.

Behaviour & compatibility

Maintain at least eight to ten of mixed sex. Other suitable schooling fishes can add security. Male rivalry intensifies color, and territorial displays may extend to similarly shaped species. Comparably sized characins, mild small bottom dwellers, or non-piscivorous medium cichlids are potential companions if space and conditions match.

Sexual dimorphism

Males grow notably larger, become more colorful, and develop strongly extended dorsal, pelvic, and anal fins. Females are rounder, especially when carrying eggs.

Breeding

It scatters eggs and provides no parental care.

Notes

Several similar species share the red shoulder mark, so it is not sufficient alone for identification. Adults of this species have a white anal-fin band covering most rays and lack the reddish wedge on the upper body seen in one close relative.

Some individuals develop metallic gold scales. The cause remains unresolved; a parasitic explanation has been suggested, but affected fish appear comfortable in reported observations. Color alone does not establish a diagnosis.