Edit Boraras naevus

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Name

Scientific name

Boraras naevus

Described by

Authority Conway & Kottelat, Year 2011

Family

Cyprinidae

Common names

Not recorded

Photograph credits

All 5 credited

Summary

Boraras naevus is a miniature cyprinid known only from the lower Tapi river drainage in Surat Thani province, southern (peninsular) Thailan…

Size and aquarium

Maximum size

20mm, standard length

Aquarium size

Minimum length 45 cm, Minimum depth 30 cm, Water movement Low: still or sluggish water

Water

Water conditions

Temperature 20–28°C, pH 5–7

Hardness

1–10dGH

Conductivity

Not recorded

Behaviour

Temperament

Peaceful

Community suitability

Community-safe

Where it lives

Countries, regions, rivers and lakes

Thailand, Tapi

Writing

Etymology

Boraras: anagram of the generic name Rasbora, in reference to the reversed ratio of abdominal and caudal vertebrae in this genus. naevus: from the Latin naevus…

Distribution

Known only from southern (peninsular) Thailand with the type series originating from a swamp north of Surat Thani city, Surat Thani province. It's been recorde…

Habitat

Inhabits shallow bodies of clear water such as swamps and marshes, with other members of the genus tending to prefer areas where submerged vegetation grows thi…

Aquarium size

Though small it still needs space to swim and dominant males will form temporary territories when spawning so a group is best kept in a tank with base dimensio…

Maintenance

Best maintained in a densely-planted aquarium and is an excellent choice for the carefully-aquascaped set-up. The addition of some floating plants and roots or…

Water conditions

Temperature: 20 – 28 °C pH: Seems to prefer slightly acidic to neutral water in the range 5.0 – 7.0. Hardness: 1 – 10 dGH

Diet

As with other Boraras species it is likely to be a micropredator feeding on small insects, worms, crustaceans and other zooplankton in nature. In the aquarium …

Behaviour and compatibility

This species is very peaceful but does not make an ideal community fish due to its small size and rather timid nature. It will do best when maintained alone or…

Sexual dimorphism

Mature females are noticeably rounder-bellied, often a little larger and less-intensively coloured than males. In males the anterior dark blotch on each flank …

Reproduction

Like many small cyprinids this species is an egg-scattering, continuous spawner that exhibits zero parental care. That is to say when in good condition and in …

Like many small cyprinids this species is an egg-scattering, continuous spawner that exhibits zero parental care. That is to say when in good condition and in the presence of both males and females relatively small numbers of eggs will be laid daily. In a well-furnished, mature aquarium it is therefore possible that small numbers of fry may start to appear without human intervention.

However if you want to increase the yield of fry a slightly more controlled approach is required. The adult group can still be conditioned together but one or more separate, perhaps 10-15 litre, containers should also be set up.

These should be very dimly lit with the base either left bare or covered with some kind of mesh of a large enough grade so that any eggs that fail to adhere to the plant can pass through but small enough so that the adults cannot reach them.

The widely available plastic 'grass'-type matting can also be used and works very well. The water itself should be of pH 5.0-6.5, 1-5°H with a temperature towards the upper end of the range suggested above. A decent-sized clump of Java moss or other fine-leaved plant should also be added filling perhaps half the available space. Filtration is not really necessary but you can use a small, air-powered sponge filter if you prefer.

Two or three pairs of well-conditioned adult fish should then be introduced to each container. It is wise to make the transfer slowly in order to avoid excessive levels of stress but if conditions are to their liking they should begin to spawn the following morning.

While this species certainly will eat its eggs it appears not to actively hunt for them as is the case with many small cyprinids. Once spawning has commenced it should continue on a daily basis.

The pair(s) should be left in situ for no more than a couple of days before being removed as the first eggs should hatch by the second day after the initial spawning. The tiny young will survive on their yolk sacs for another 24 hours or so after which they will require Paramecium or other microscopic food.

After a week to ten days they should be large enough to accept Artemia nauplii/microworm etc. As the days pass additional fry should start to appear from later spawning events. It's best to wait a week or two before starting to perform small water changes in order to avoid unduly shocking the young fish.

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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 pageFor example, the Behaviour and compatibility section already says this.

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Year

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Notes

Prior to description this species was traded under various names including B. sp. 'micros' or 'red micros', B. sp. 'Petch Noi', B. sp. 'Thailand', B. sp. 'sout…

References

7 on this profile

Name

Scientific name

Described by

Family

Common names

Photograph credits

Summary

Size and aquarium

Maximum size

Aquarium size

Water

Water conditions

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries, regions, rivers and lakes

Writing

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References