Edit Iriatherina werneri

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Name

Scientific name

Iriatherina werneri

Described by

Authority Meinken, Year 1974

Family

Melanotaeniidae

Summary

The threadfin rainbowfish, Iriatherina werneri, is a small rainbowfish from southern New Guinea, Cape York in Queensland and the Northern T…

Size and aquarium

Maximum size

40mm, standard length

Tank size

Minimum length 60 cm, Minimum depth 30 cm, Water movement Low: still or sluggish water

Water

Temperature and pH

Temperature 22–30°C, pH 5–8

Hardness

1–12dGH

Conductivity

Not recorded

Behaviour

Temperament

Peaceful

Community suitability

Community-safe

Where it lives

Countries

Australia, Indonesia, Papua New Guinea

Supporting text

Etymology

Not written yet

Distribution

Described from 'Merauke, Irian Jaya, Indonesia' which corresponds to modern day Merauke Regency, Papua province, Indonesia, on the island of New Guinea. It's d…

Habitat

Shows a preference for slow-moving streams, freshwater swamps, lagoons, and billabongs containing clear water and abundant macrophytes. It's most commonly-foun…

Aquarium size

An aquarium with base dimensions of 60 ∗ 30 cm24 ∗ 12 in should be the smallest considered.

Maintenance

Best kept in a densely-planted tank and an excellent choice for the carefully-aquascaped set-up. The addition of some floating plants and driftwood roots or br…

Water conditions

Not written yet

Diet

Feeds on floating or suspended phytoplankton, diatoms, and other zooplankton in nature, and in the aquarium must be offered items of a suitable size for its ti…

Behaviour and compatibility

Very peaceful but not suitable for the general community aquarium since it's easily outcompeted for food and the long fins of mature males may be nipped at by …

Sexual dimorphism

Adult males possess extended unpaired and pelvic fins, are larger and more colourful than females.

Reproduction

This species is an egg-scatterer exhibiting no parental care and will consume its own eggs and fry given the opportunity. Spawning is more likely in temperatur…

This species is an egg-scatterer exhibiting no parental care and will consume its own eggs and fry given the opportunity. Spawning is more likely in temperatures towards the upper end of the range suggested above, with females capable of depositing a few eggs daily for a period of several days. An individual male may also mate with multiple females during a single day, and spawning usually continues throughout daylight hours during warmer periods.

Males will often display to females when in spawning condition and appear to prefer to do so under cover of floating vegetation. Overall colouration intensifies, the rounded first dorsal-fin is held erect and a 'flicking' gesture of the filamentous rays of the second dorsal and anal fins used to entice a mate. A responsive female will select a spawning site, typically the roots of floating plants or a bunch of fine-leaved vegetation, and signify she has done so by remaining still, at which point both fish enter the medium to release eggs and milt.

There exist two basic methods for aquarium breeding. The first involves isolating a single male and two or three females into a smaller tank set up with an air-powered sponge filter and spawning medium in the form of nylon mops or aquatic moss. The medium is checked on a daily basis and removed to a separate hatching container when eggs are found.

The alternative is to maintain a colony of adults in a larger, fully-decorated set-up which if well-planted should allow some fry to survive. Since they spend the early part of life close to the water surface aquatic mosses from the genus Taxiphylum attached to décor high in the water column apparently produce the most favourable results, but floating plants with trailing roots are also recommended.

The latter approach is less productive but simpler and more reliable as mature, planted aquaria normally facilitate relatively stable water conditions and the resident microfauna can constitute a valuable early food source for fish fry. When the eggs are isolated and fry raised artificially issues can arise with both feeding and water quality due to their incredibly small size and delicate nature.

Aged water can result in high mortality so regular, small water changes are essential and uneaten food should not be allowed to accumulate in the rearing tank. The fry are also quite selective in terms of preferred prey size as they grow, so if using live foods cultures of several types may be necessary. They can also be raised using good quality, powdered dry products of which some are available in incrementally-graded particle sizes. Small meals should be offered at least twice daily.

Growth rate is generally slow for the first couple of weeks, but can be improved by the use of live foods, and the faster and slower-growing fry may require separation at some point as the larger will outcompete and prey on the smaller.

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Where does this come from?

My own experienceFor example, I've kept twelve in a planted 60 cm tank since March 2024.A website I sawFor example, an IUCN Red List assessment, a museum catalogue or a FishBase page.A paperFor example, Marshall et al. (2011), Water temperature differences in interfluvial palm swamp habitats of Paracheirodon axelrodi and P. simulans.A book, or something not onlineFor example, Tappin (2010), Rainbowfishes: their care and keeping in captivity.Something already on the profileFor example, the Behaviour and compatibility section already says this.

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Year

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Notes

Although this species is widely-traded and produced on a commercial scale for the aquarium hobby, it's actually quite delicate with some rather specific care r…

References

4 on this profile

Name

Scientific name

Described by

Family

Summary

Size and aquarium

Maximum size

Tank size

Water

Temperature and pH

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries

Supporting text

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References