All fish / Characidae

Ruby Tetra

Axelrodia riesei

Also known as ruby tetra, red riesei tetra, riesei tetra, ruby red tetra, axelrodia riesei, red tetra, ルビーテトラ, 红宝石灯

A tiny tetra that turns deep ruby red with an orange tint when settled in soft, acidic water, and its eyes have a red upper rim too. Keepers like it for planted or blackwater nano tanks, where a large group adds strong colour without crowding the tank.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

2.5 cm

Temperature

22 to 27 °C

pH

5 to 7

Smallest tank

40 litres

Keep as

Shoal of 10 or more

Diet

Omnivore: small live and frozen foods such as daphnia, cyclops and baby brine shrimp, plus fine flakes and micro pellets

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Upper Rio Meta basin, Colombia

Breeding

It scatters eggs among fine plants and gives no parental care. Few spawnings in captivity have been reported, so soft, acidic water, dim light and a separate tank to keep the eggs safe from adults are thought to be needed.

Good to know

Wild-caught fish are often sold looking pale and stressed, so give them time to settle and colour up. Only keep it with very small, peaceful tankmates.