Blue-Eye Blue Black - Brackish 2cm

Blue-Eye Blue Black - Brackish

Pseudomugil cyanodorsalis, commonly known as the Blue Black Blue-Eye, is a fascinating nano rainbowfish that thrives in fresh, brackish and full saltwater environments. These small but stunning fish are perfect for aquarists looking to add a splash of colour to their brackish setups or even a unique species to a small marine tank. Their hardy nature and striking appearance make them an excellent choice for both beginner and experienced aquarists.

The Blue Black Blue-Eye is named for its distinctive bright blue eyes and the striking blue-black coloration that runs along its dorsal nape. These fish have a slender, elongated body that reaches a maximum length of around 3 cm. Their vibrant blue colour is most intense on the top of their bodies, gradually fading into a lighter shade on the sides. The fins are often transparent with subtle blue highlights, adding to their delicate beauty. These fish display their colours best when kept in schools, where their collective movement can create a mesmerising visual effect.

Breeding Blue-Eye Blue Blacks in captivity is relatively straightforward, given the right conditions. They are egg scatterers and will spawn readily in a well-maintained aquarium with plenty of hiding spots and spawning mops. Males are typically more colourful and slightly larger than females, making sexing relatively easy. Providing a diet rich in live and frozen foods can help condition them for breeding.

Tank Recommendations for your Blue-Eye Blue Black - Brackish
Being a very small and peaceful fish, the Blue Black Blue-Eye can be kept in nano aquariums with a minimum volume of 40 litres. These fish are primarily middle to top dwellers and will appreciate a tank with plenty of horizontal swimming space. A tight-fitting lid is essential as they are known to be jumpers. They thrive in a brackish environment with a salinity of around 1.005-1.010 and will do well in temperatures ranging from 22-28°C. A sandy substrate with plenty of plants and hiding spots will help replicate their natural habitat and make them feel at home.

Suitable Tank Buddies
Being a small and peaceful fish these blue eyes are a very easy fish to pair with other tank mates. They can be kept in aquariums with other dwarf rainbow fish or in mixed community aquariums.

Usually Compatible
Pseudomogil species such as forktail rainbows, neon blue eyes and smaller brackish fish like bumblebee gobies or mudskippers

Sometimes Compatible
Medium size growing rainbows such as neon rainbows, Murray river rainbows and larger community fish like gouramis. Though these fish may be okay temperament wise they would be far too boisterous for the small blue eye.

Rarely Compatible
Large and aggressive species which would prey on the blue eye or fin nipping species like tiger barbs.

Feeding your Blue-Eye Blue Black - Brackish
The Blue Black Blue-Eye is very easy to feed once it is settled into the aquarium. It will readily eat a wide range of foods but would prefer to have high protein-rich options like bloodworms, Mysis shrimp, or live foods such as brine shrimp.

This however can be substituted with good quality flakes or nano floating pellets. Feeding should happen once during the day during lighting hours.