All fish / Danionidae

Blue Axelrod's Rasbora

Sundadanio axelrodi

Also known as axelrod's rasbora, blue axelrodi rasbora, green axelrodi rasbora, red axelrodi rasbora, sundadanio, sundadanio sp. 'green', sundadanio sp. 'red', rasbora axelrodi, スンダダニオ・アクセルロディ, seluang, 阿氏巽他波鱼, 蓝钻灯

A tiny peat swamp fish barely 2 cm long, with males showing an iridescent blue or green line along the body and red tones on the fins, depending on the population. Keepers prize it as a jewel for soft, acidic blackwater nano tanks with dim light and leaf litter.

Care at a glance

Care level

Hard

Temperament

Peaceful

Adult size

2 cm

Temperature

22 to 28 °C

pH

4 to 6.5

Smallest tank

30 litres

Keep as

Group of 10 or more

Diet

Carnivore: tiny live and frozen foods such as daphnia, cyclops, artemia nauplii and microworms, plus fine dry food

Swims

Middle of the tank

Lifespan

2 to 3 years

Water

Freshwater

Wild range

Borneo (Kalimantan, Sarawak), Bangka, Sumatra and Riau islands, Indonesia and Malaysia

Breeding

It scatters a few eggs among fine plants or moss and gives no parental care. Breeding is possible in very soft, acidic water, but fry are minute and need infusoria, so success is uncommon.

Good to know

Needs very soft, acidic, stable water and is easily outcompeted by larger fish, so keep it alone or with other small blackwater species. Several regional colour forms are sold under different trade names and may be undescribed species.