Threadfin Rainbow Fish Iriatherina Werneri 5cm
Image for illustration purposes only. Exact colours, patterns, and size may vary between individuals.
Delivered alive, guaranteed
Live fish delivery is £20 per order, delivered Thursday, Friday or Saturday, arriving before 1:00pm on the day you choose at checkout. Packed by aquatic specialists and shipped overnight with a dedicated livestock courier, every fish is covered by our Live Arrival Guarantee with automatic refunds. See How Live Fish Delivery Works for full details.
When will my fish arrive?
| Order placed | Delivery day |
|---|---|
| Up to Monday 11:00am | Thursday (that week) |
| Monday after 11:00am – Tuesday 11:00am | Friday (that week) |
| Tuesday after 11:00am – Wednesday 11:00am | Saturday (that week) |
| Wednesday after 11:00am – Sunday (any time) | Thursday (following week) |
Overview
The Threadfin Rainbowfish is a delicate, elegant micro-fish: males trail long thread-like dorsal and anal fin extensions and fan them in constant displays. It lives in slow, weedy swamps and billabongs of southern New Guinea and northern Australia. It suits calm, mature planted species or nano tanks.
- Adult Size: Around 4–5 cm (1.6–2 in) including fin filaments on males
- Lifespan: 2–3 years
Origin
- Native to: Southern New Guinea and Cape York, Australia
- Habitat: Slow streams, swamps, lagoons and billabongs with dense plants
Feeding
- Diet: Omnivorous, favouring tiny live foods
- Preferred Foods: Daphnia, Moina, brine shrimp nauplii, micro worms, copepods, crushed flake
- Feeding Habits: Small feeds two or three times daily; very small mouth
Tank Mates
- Best with: Groups of 6–10 of its own kind, small blue-eyes, pygmy Corydoras, shrimp
- Avoid: Any boisterous, fast-feeding or fin-nipping fish, including most tetras and barbs
Aggression & Behaviour
- Temperament: Very peaceful and timid
- Territoriality: None; males only display to rivals
Experience Level
- Difficulty: Intermediate
- Challenges: Easily outcompeted; sensitive to instability and large water changes
Water Parameters
- Water Type: Freshwater, soft to moderately hard, slightly acidic to neutral
- Temperature: 24–28°C (75–82°F)
- pH: 6.0–7.5
- Hardness: 2–12 dGH
- Flow: Slow
- Tank Size: Minimum 60 litres; species tank or with equally gentle fish
Final Notes
Transport stresses this species, so a settled, mature tank with dense planting and floating cover is the key to success; small, frequent water changes suit it far better than large ones. Not a standard community fish: those long fins invite nipping. Egg scatterers, they spawn daily in warm water among floating plant roots, with no parental care. Settled in, they are one of the most graceful fish available.
Please Note
The livestock that is sold on our online site is not held in store at our Birchwood Aquatic Centre shop. Species sold at the Birchwood Aquatic Centre physical store may differ from ones available to order to your door.
Frequently Asked Questions
In insulated boxes designed for live transport, packed by aquatic specialists,
overnight with a licensed live-animal courier, arriving before 1pm.
It is covered by our Live Arrival Guarantee.
Photograph it within 4 hours of delivery, email info@birchwoodaquaticcentre.co.uk with your order number, and the refund is processed automatically. The cover continues for 7 days after arrival.
Wednesday, Thursday, Friday and Saturday. You pick your day at checkout; please choose a day someone is home.
Yes. One basket, one checkout; the fish arrive with the specialist courier and the rest of your order ships as normal.
We can deliver to UK mainland only for live fish.
Follow the five-minute acclimatisation steps in our When Your Fish Arrive guide: float the bags, add tank water gradually, net the fish in, lights low, feed tomorrow.