All fish / Pseudomugilidae

Blueback Blue-eye

Pseudomugil cyanodorsalis

Also known as blue back blue eye, blueback blueeye, blue-back blue-eye, blueback rainbowfish, pseudomugil cyanodorsalis, シアノドルサリス, 蓝背燕子

A tiny, slender blue-eye in which mature males show a bright metallic blue back and pale fins edged with white or yellow. It comes from mangrove creeks and tidal flats, so it suits small brackish set-ups and peaceful nano tanks where its display behaviour can be watched up close.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

3 cm

Temperature

24 to 30 °C

pH

7 to 8.5

Smallest tank

40 litres

Keep as

Group of 6 or more, more females than males

Diet

Carnivore: small live and frozen foods such as brine shrimp, daphnia and cyclops, plus fine flake

Swims

Top of the tank

Lifespan

1 to 3 years

Water

Brackish

Wild range

Northern Australia (coastal Northern Territory and Western Australia)

Breeding

Pairs scatter a few eggs daily over fine plants or spawning mops over several days. Eggs hatch in roughly one to two weeks and the fry need infusoria or other very fine foods, so breeding is fairly straightforward if eggs are removed from the adults.

Good to know

Does best in hard, alkaline or slightly brackish water and can struggle in soft acidic conditions. Very small and short-lived, so keep only with equally gentle tankmates.