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Threadfin Rainbowfish
IntermediateIriatherina werneri
Small rainbowfish with thread-like elongated fins. Each fin extends like thread, with an elegant swaying appearance in water. Ideal for single-species small tanks or as an accent in planted tanks. Prefers gentle water flow.
Difficulty
Intermediate
Temperature
24〜28℃
Lifespan
3-4 years
Size
3-4cm
Diet
Frozen brine shrimp, infusoria, micro pellets
About
The threadfin rainbowfish (Iriatherina werneri) is the sole species in its genus, native to shallow swamps, flooded grasslands, and slow-moving streams from the Fly River system in southern New Guinea through the Cape York Peninsula of northern Queensland, Australia. Growing to 4–5 cm, males develop extraordinary elongated fin rays on the dorsal, anal, and caudal fins — extensions so delicate and flowing that the fish has been described as 'an underwater butterfly.' The effect in a well-planted, calm aquarium is genuinely otherworldly. Water conditions of pH 6.5–7.5 at 24–28°C are appropriate. The primary care challenge is protecting the gossamer fins: even moderate water current shreds them irreparably, making sponge filters or extremely gentle flow sources essential. Any fin-nipping fish is strictly incompatible. Their tiny mouths require micro-sized foods exclusively: powdered fry foods, baby brine shrimp nauplii, and micro worms. Breeding on fine plants is achievable, though fry are extremely small and require infusoria for initial feeding. A fish of exceptional elegance and fragility, best suited to a purpose-designed, species-appropriate nano or botanical aquarium.
Source: Wikipedia (CC BY-SA 4.0)
Basic Info
Origin
Southern New Guinea and Cape York Peninsula, northern Queensland, Australia
Lifespan
3-4 years
Size
3-4cm
Temperature
24〜28℃
Diet
Frozen brine shrimp, infusoria, micro pellets
Care Guide
Care Specifications
- pH
- 6–8
- Hardness (GH)
- 5–12 dGH
- Water Temp.
- 26–30℃
PeacefulGroupBreeding: Hard
Sources: FishBase / Seriously Fish
References & Sources
Edited & verified by: br-choku editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Taxonomy & Authority
Regulations & Conservation Status
Not CITES-listed
Sources: FishBase / Seriously Fish / CITES Appendices (Checklist)
Regulations may change. Always verify the latest information with the relevant authorities.
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