Green fire tetra

Aphyocharax rathbuni

A green-silver body with red along the rear underside

The red area extends along the rear belly towards the tail. Fin colour changes with sex and breeding condition.

Adult length: Up to 7.1 cm (standard length, without the tail fin)
Water temperature: 20–26 °C
pH: 6.5–7.5
Hardness: 2–20 dGH

Natural habitat: Native to the Paraguay River basin.

Fin nipping occurs. Avoid slow, long-finned companions and watch much smaller fish.

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Appearance and identification

Compare the location of the red area and the normally clearer dorsal and pelvic fins with Aphyocharax anisitsi. Breeding males can develop different dark and pale fin markings. Females become fuller-bodied in spawning condition.

Same-species behaviour

Keep at least six. A larger group does not stop fin nipping.

Space requirements

A 60 × 30 cm footprint suits a small group. Combine shelter with open swimming room.

Diet and feeding

Offer suitably sized prepared foods with small live or frozen foods. It cannot live on aquarium algae alone.

Compatibility limits

Check fin shape, size and feeding competition.

Aquarium environment

Plants, sand and wood can provide shelter around an open swimming area.

Sources

www.fishbase.se ↗ 2026-10-25

www.seriouslyfish.com ↗ 2026-10-22

www.acshop.com.tw ↗ 2026-10-22

www.practicalfishkeeping.co.uk ↗ 2026-10-22

www.researchgate.net ↗ 2026-10-22

researcharchive.calacademy.org ↗ 2026-10-22