Red phantom tetra

Megalamphodus sweglesi

A dark shoulder patch on a reddish body, with extended male fins

The dark shoulder patch stands out. Mature males have extended dorsal and anal fins. Redder and paler colour forms are one species.

Adult length: Up to 3.5 cm (standard length, without the tail fin)
Water temperature: 20–28 °C
pH: 4.5–7.5
Hardness: 1–12 dGH

Natural habitat: Native to the Orinoco River basin.

Small size does not make it suitable for a short aquarium. Males form temporary dominance relationships and need space and retreat areas.

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Appearance and identification

Check the shoulder patch and body shape, then account for sex: females are deeper-bodied and males have longer fins. This reddish species is distinct from the black phantom.

Same-species behaviour

Keep eight to ten or more in a mixed-sex group. Expect displays and competition, not constant tight schooling.

Space requirements

Allow a footprint of at least 80 × 30 cm, with cover and swimming space.

Diet and feeding

Offer small dry foods with appropriately sized frozen or live foods for variety.

Compatibility limits

Check companion size, predation and space requirements individually.

Aquarium environment

Plants and branching wood provide cover.

Sources

www.fishbase.se ↗ 2026-10-25

www.seriouslyfish.com ↗ 2026-10-22

researcharchive.calacademy.org ↗ 2026-10-22

mw-fish.com.tw ↗ 2026-10-22

wenyensu.shopstore.tw ↗ 2026-10-22