KeepingFishSimple | SKU: LIVE-FISH-THREADFIN-RAINBOWFISH-1PK

Threadfin Rainbowfish - 4cm (Iriatherina werneri) (Live Fish)

Name: Threadfin Rainbowfish - 4cm (Iriatherina werneri) (Live Fish)
Brand: KeepingFishSimple
SKU: LIVE-FISH-THREADFIN-RAINBOWFISH-1PK
Price: 29.95 AUD
Availability: InStock

$29.95 AUD ~~$39.95~~

Tax included

Size, Colour & Sex

Appearance & Colour

Fish may vary from the images shown. Colour, patterns, markings and fin shapes can differ naturally between individuals and may change with age, sex, stress and environmental conditions.

Size

All sizes are approximate and provided as a guide. Individual fish may be slightly larger or smaller than advertised.

Sex Requests

Want a male or female? Leave a note at checkout and we'll do our best to accommodate your request. However, we cannot guarantee a particular sex due to availability and the difficulty of sexing some species.

For customers wanting to select specific fish, we recommend visiting us in-store.

For more information, please see our Store Policies.

Acclimation Guide

1. Prepare Your Aquarium

Make sure your aquarium is fully cycled, with 0 ammonia and 0 nitrite, and the temperature is suitable for your new fish.

2. Start Drip Acclimation

Place your fish and their transport water into a clean container. Using airline tubing, slowly drip water from your aquarium into the container at approximately 2–4 drops per second.

3. Slowly Add Aquarium Water

Over the next 30–60 minutes, allow the water volume to approximately double. This helps your fish gradually adjust to their new water conditions.

4. Transfer Your Fish

Gently net your fish into their new aquarium. Avoid adding transport water to your tank.

5. Give Them Time to Settle

Keep the aquarium lights off for a few hours and wait until the following day before feeding.

Important: Arrived with an issue?

If any fish arrive dead (DOA), keep the transport bag sealed and contact us within 24 hours with clear photos of the fish inside the unopened bag.

See our DOA Policy for more information.

Delivery & Shipping

Important: Live Fish Delivery

Please provide accurate contact details and ensure someone is available to receive your fish. This is essential for their safe arrival.

Shipping Costs

We offer discounted shipping on larger livestock orders, with FREE shipping on orders over $400!

Live Fish Shipping Rates

Under $150: $39.95

$150–$249.99: $29.95

$250–$349.99: $19.95

$350–$399.99: $9.95

$400+: FREE SHIPPING

Please view our shipping policy for more information.

The Threadfin Rainbowfish is a delicate freshwater fish with a silvery to bluish body accented by subtle iridescent gold and reddish tones. Its elongated, thread-like fin extensions and flowing translucent fins give it a distinctive, graceful appearance.

Common names: Threadfin Rainbowfish, Featherfin Rainbowfish, Werner's Rainbowfish
Scientific name: Iriatherina werneri
Approximate size: 3–4 cm
Temperament: Very peaceful and delicate; best kept in groups of 6 or more
Recommended tank size: 60 L or larger
Diet: Omnivorous/micro-predatory; feed finely crushed flakes, micro-pellets, daphnia, baby brine shrimp, cyclops, and other very small foods
Origin: Northern Australia and southern New Guinea
Basic care information: Keep in a mature, densely planted aquarium with gentle flow and plenty of cover. Provide clean, soft to moderately hard water around 23–28°C, preferably slightly acidic to neutral. Their tiny mouths require appropriately sized food, and slow feeding behavior means they can be outcompeted by faster tankmates. Males develop spectacular elongated dorsal and anal fins with thread-like extensions and stronger coloration, while females have shorter, rounded fins. Avoid fin-nipping or boisterous tankmates.