Threadfin Rainbowfish Iriatherina werneri 4-5cm

Description

Threadfin Rainbowfish (Iriatherina werneri)

An elegant nano rainbowfish famous for its flowing thread-like fins, shimmering iridescent colours, and graceful display behaviour in planted aquariums.

Quick Facts

  • Scientific name: Iriatherina werneri
  • Common name: Threadfin Rainbowfish
  • Adult size: 4–5 cm
  • Tank size: 60L+ recommended
  • Difficulty: 🟡 Intermediate
  • Temperament: Peaceful
  • Best kept: Schools of 8 or more

Is this for you?

✔️ Perfect if:

  • You love elegant nano fish with flowing fins.
  • You keep peaceful planted aquariums.
  • You enjoy natural courtship displays.
  • You want a true feature fish for a community aquarium.

❌ Avoid if:

  • You keep fin-nipping fish such as Tiger Barbs.
  • You have aggressive or boisterous tank mates.
  • You plan on keeping only one or two fish.
  • Your aquarium has excessive water flow.

Why choose Threadfin Rainbowfish?

Threadfin Rainbowfish are among the most elegant freshwater fish available. Mature males develop spectacular thread-like extensions on their dorsal and anal fins, creating a graceful appearance unlike almost any other nano fish.

Their subtle iridescent blues, yellows and reds shimmer under aquarium lighting, while the males spend much of the day displaying to one another by extending their magnificent fins in peaceful competitions.

When kept in heavily planted aquariums with plenty of open swimming space, Threadfins become incredibly confident and reward their owners with one of the most beautiful courtship displays in the aquarium hobby.

Common mistakes

  • Keeping them with fin-nipping fish.
  • Housing them with large aggressive species.
  • Keeping too few individuals.
  • Using excessive filter flow.
  • Providing little plant cover.

Care made simple

  • Temperature: 24–28°C
  • pH: 6.0–7.5
  • Diet: Premium nano pellets, baby brine shrimp, daphnia, microworms and frozen foods
  • Water: Clean, stable and well-filtered with gentle flow
  • Setup: Heavily planted aquarium with open swimming areas, floating plants and a secure lid

Pairs perfectly with

  • Pseudomugil species
  • Ember Tetras
  • Corydoras
  • Otocinclus
  • Java Moss and fine-leaved aquatic plants
NTA Insight:
Threadfin Rainbowfish aren't about bold colours—they're about elegance. Mature males displaying their long flowing fins amongst lush plants create one of the most mesmerising displays you'll ever see in a freshwater aquarium. They're best appreciated in calm, peaceful aquariums where their delicate finnage remains in perfect condition.

FAQ

How many Threadfin Rainbowfish should I keep?

They are schooling fish and should be kept in groups of at least eight. Larger groups encourage natural behaviour and reduce stress.

Can they live with shrimp?

Yes. Adult shrimp are generally safe, although tiny shrimplets may occasionally be eaten. Dense mosses provide excellent shelter.

Are they suitable for beginners?

They are best suited to hobbyists with stable, mature aquariums. While not difficult to keep, they appreciate excellent water quality and peaceful surroundings.

Can Threadfin Rainbowfish breed in aquariums?

Yes. They readily spawn among fine-leaved plants or spawning mops, and with a little care the fry can be successfully raised in home aquariums.

Why are they called Threadfin Rainbowfish?

Mature males develop spectacular thread-like extensions on their fins, giving them an elegant appearance that inspired their common name.

Threadfin Rainbowfish Iriatherina werneri 4-5cm

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$20.00


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    Description

    Threadfin Rainbowfish (Iriatherina werneri)

    An elegant nano rainbowfish famous for its flowing thread-like fins, shimmering iridescent colours, and graceful display behaviour in planted aquariums.

    Quick Facts

    • Scientific name: Iriatherina werneri
    • Common name: Threadfin Rainbowfish
    • Adult size: 4–5 cm
    • Tank size: 60L+ recommended
    • Difficulty: 🟡 Intermediate
    • Temperament: Peaceful
    • Best kept: Schools of 8 or more

    Is this for you?

    ✔️ Perfect if:

    • You love elegant nano fish with flowing fins.
    • You keep peaceful planted aquariums.
    • You enjoy natural courtship displays.
    • You want a true feature fish for a community aquarium.

    ❌ Avoid if:

    • You keep fin-nipping fish such as Tiger Barbs.
    • You have aggressive or boisterous tank mates.
    • You plan on keeping only one or two fish.
    • Your aquarium has excessive water flow.

    Why choose Threadfin Rainbowfish?

    Threadfin Rainbowfish are among the most elegant freshwater fish available. Mature males develop spectacular thread-like extensions on their dorsal and anal fins, creating a graceful appearance unlike almost any other nano fish.

    Their subtle iridescent blues, yellows and reds shimmer under aquarium lighting, while the males spend much of the day displaying to one another by extending their magnificent fins in peaceful competitions.

    When kept in heavily planted aquariums with plenty of open swimming space, Threadfins become incredibly confident and reward their owners with one of the most beautiful courtship displays in the aquarium hobby.

    Common mistakes

    • Keeping them with fin-nipping fish.
    • Housing them with large aggressive species.
    • Keeping too few individuals.
    • Using excessive filter flow.
    • Providing little plant cover.

    Care made simple

    • Temperature: 24–28°C
    • pH: 6.0–7.5
    • Diet: Premium nano pellets, baby brine shrimp, daphnia, microworms and frozen foods
    • Water: Clean, stable and well-filtered with gentle flow
    • Setup: Heavily planted aquarium with open swimming areas, floating plants and a secure lid

    Pairs perfectly with

    • Pseudomugil species
    • Ember Tetras
    • Corydoras
    • Otocinclus
    • Java Moss and fine-leaved aquatic plants
    NTA Insight:
    Threadfin Rainbowfish aren't about bold colours—they're about elegance. Mature males displaying their long flowing fins amongst lush plants create one of the most mesmerising displays you'll ever see in a freshwater aquarium. They're best appreciated in calm, peaceful aquariums where their delicate finnage remains in perfect condition.

    FAQ

    How many Threadfin Rainbowfish should I keep?

    They are schooling fish and should be kept in groups of at least eight. Larger groups encourage natural behaviour and reduce stress.

    Can they live with shrimp?

    Yes. Adult shrimp are generally safe, although tiny shrimplets may occasionally be eaten. Dense mosses provide excellent shelter.

    Are they suitable for beginners?

    They are best suited to hobbyists with stable, mature aquariums. While not difficult to keep, they appreciate excellent water quality and peaceful surroundings.

    Can Threadfin Rainbowfish breed in aquariums?

    Yes. They readily spawn among fine-leaved plants or spawning mops, and with a little care the fry can be successfully raised in home aquariums.

    Why are they called Threadfin Rainbowfish?

    Mature males develop spectacular thread-like extensions on their fins, giving them an elegant appearance that inspired their common name.

    Live Arrival & Ordering FAQ

    Why do livestock prices sometimes change?

    Unlike manufactured products, fish and shrimp continue to grow and develop over time. Their value changes as they increase in size, develop colour, or become breeding pairs.

    Our prices are based on the current size, quality and availability of each specimen. While pricing often remains stable for around 3–4 months, it may be updated at any time to reflect these changes.

    We always aim to offer healthy, high-quality livestock at fair and competitive prices.

    Do you offer a live arrival guarantee?

    Yes. All livestock is covered by our Live Arrival Guarantee.

    In the rare event of DOA, please contact us promptly with clear photos of the livestock in the original unopened bag.

    Please review our full DOA and store policies before purchase.

    Can you ship to all states in Australia?

    No. Due to state restrictions, we cannot ship livestock or live plants to WA and TAS.

    What should I check before ordering?

    Before placing an order, make sure:

    • Your tank is fully cycled and stable
    • Your aquarium has enough space for the species
    • Your current livestock are compatible in temperament, size, and requirements
    • Your water parameters, habitat, and temperature suit the species
    • You are not adding too many fish at once
    What should I expect when my fish arrives?

    It is normal for fish, shrimp, or snails to look pale, stressed, or less active after shipping.

    This is temporary. Most livestock will settle and regain colour within a few days.

    How long does it take for fish to settle in?

    Most livestock will take 3–7 days to fully adjust to their new environment.

    Should I feed my fish immediately after arrival?

    No. We recommend waiting 24 hours before feeding to allow them to settle.

    If you already have fish in your tank, feeding them before introducing new arrivals can help reduce stress.

    Why do fish sometimes struggle after being added to a tank?

    In most cases, issues are caused by tank conditions, not shipping.

    • Uncycled or unstable tanks
    • Poor water parameters
    • Overstocking
    • Unsuitable tank mates
    What is Nano Tanks Australia’s main tip for new livestock?

    Most livestock losses happen in immature or unstable tanks, not during shipping.

    If your setup is not fully established, the risk to new arrivals is significantly higher.

    Not sure if this fish is right for your setup?

    If you are unsure whether this species suits your setup, contact us before ordering and we’ll help point you in the right direction.

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