Threadfin Rainbowfish
Iriatherina werneri
Origin: Southern New Guinea, northern Australia
Water Parameters
Quick Stats
- Max Size
- 4 cm
- Min Tank
- 40 L
- Lifespan
- 3–5
- Swimming Level
- upper
- Schooling
- Yes (6+)
- Diet
- omnivore
- Temperament
- Very peaceful; vulnerable to fin-nippers
About
Iriatherina werneri, the Threadfin Rainbowfish, is a tiny jewel among rainbowfishes. Males bear extraordinary elongated filaments extending from all fins — vivid yellows, reds, and blacks. Reaching only 4 cm, it is a true nano species best kept in species tanks or with very gentle micro-fish. Native to shallow, sheltered waters of southern New Guinea and northern Australia. Delicate and sensitive; requires pristine water and no fin-nipping tankmates.
Care Guide
Species tank or nano setup with very gentle fish only. Temperature 24–28 °C. Soft to medium water. Feed micro-foods: micro-pellets, baby brine shrimp, micro-worm. No strong flow — delicate fins. 40+ L for a small group. Weekly water changes essential.
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