Metallic livebearer

Girardinus metallicus

Black-chin males show a dark underside extending into the gonopodium; females are larger and plainer.

Adult length: Up to 6 cm (standard length, without the tail fin)
Water temperature: 22–27 °C
pH: 6–8
Hardness: 8–20 dGH

Provide refuges from male pursuit; confirm stock water conditions rather than assuming salt is required.

Appearance and identification

In the illustrated black-chin male, follow the dark underside from the mouth into the long gonopodium. Females are plainer and cannot be identified by this male colour pattern. Compared with the representative G. falcatus male, the dark underside is more conspicuous; check sex and morph rather than identifying species by the amount of black alone.

Same-species behaviour

Seriously Fish reports persistent male pursuit and recommends several females per male to spread attention. This is not a validated fixed ratio or group capacity. A Chicago Livebearer Society keeper also observed male pursuit and provided refuges for females.

Space requirements

The source lists a 45 × 30 cm base without a group count. Provide refuges from male pursuit; this is not a stocking capacity.

Diet and feeding

Offer varied small foods with plant material; grazing does not replace feeding.

Compatibility limits

Seriously Fish discusses companions separately for hard freshwater and brackish conditions. Confirm the stock’s previous water, then check each candidate’s water requirements, size and behaviour. A peaceful description does not make every small fish compatible, and a brackish record does not mean every stock needs salt.

Aquarium environment

Seriously Fish recommends ample planting with some floating cover. The Chicago keeper used Java moss and floating artificial plants for shelter; adults could still pursue fry, so hiding places do not guarantee survival. Plant-specific damage and a numerical flow recommendation remain unknown.

Sources

www.seriouslyfish.com ↗ 2026-10-22

www.chicagolivebearer.com ↗ 2026-10-22

riverparkaquatics.co.uk ↗ 2026-10-22

api.gbif.org ↗ 2026-10-22