Bleeding heart tetra

Megalamphodus erythrostigma

A red shoulder mark and extended fins in mature males

The red shoulder patch is conspicuous, but several related species share it.

Adult length: Up to 6 cm (standard length, without the tail fin)
Water temperature: 21–28 °C
Lifespan: Up to 3 years
pH: 4–7.5
Hardness: 1–12 dGH

Native range: Native to the upper Amazon basin.

Natural habitat: Unknown

Mature males may defend space against their own species and similarly shaped fish. Avoid immature aquaria and accumulation of organic waste.

View comparison →

Appearance and identification

The rosy tetra lacks this prominent red shoulder patch. M. socolofi and M. pyrrhonotus also have red shoulder marks, so check the anal-fin white band and whether a red wedge appears on the back. In adults, the white anal-fin band extends across most rays, farther than in M. socolofi. This species lacks the red wedge on the upper body of M. pyrrhonotus.

Same-species behaviour

Keep at least eight to ten in a mixed-sex group; ten to fifteen or more is also suggested.

Space requirements

Allow a footprint of at least 90 × 30 cm, with room for adult body depth, male territorial behaviour and swimming.

Diet and feeding

Offer suitable dry foods with live or frozen foods and some food containing plant or algal material.

Compatibility limits

Assess companion size and male competition. A peaceful label does not guarantee safety for similarly shaped fish or small shrimp.

Aquarium environment

Plants, floating cover and wood provide shaded areas while leaving open swimming space.

Sources

www.fishbase.se ↗ 2026-10-25

www.seriouslyfish.com ↗ 2026-10-22

researcharchive.calacademy.org ↗ 2026-10-22

www.aquariumglaser.de ↗ 2026-10-22

w.tbs-aqua.com ↗ 2026-10-22

animaldiversity.org ↗ 2026-10-22

aqua.org ↗ 2026-10-22