Freshwater Fish
Neon Blue-Eye
A vivid, electric-blue nano rainbowfish from coastal Australia with a neon blue dorsal stripe and semi-transparent body. One of the most intensely coloured small fish in the freshwater hobby and exceptionally compatible with shrimp.
Neon Blue-Eye (Pseudomugil cyanodorsalis), also known as the Neon Blue-Eye or Cyanodorsalis Blue-Eye, is a coastal Australian nano rainbowfish with a vivid electric-blue dorsal stripe running along the top of the body from the head to the tail -- the neon intensity of which is the species' most immediately striking characteristic. The body is semi-transparent with silver and pale yellow tones, and the eyes have the characteristic vivid blue of the Pseudomugil genus. Adult males develop extended fins that they display continuously. Unlike most other Pseudomugil species that prefer soft, acidic water, P. cyanodorsalis is naturally a coastal species that tolerates and even prefers harder, slightly alkaline water and can adapt to low-salinity brackish conditions, making it unusual in the genus and well-suited to standard Neocaridina setups. Peaceful, active, and among the most shrimp-compatible fish available due to its tiny mouth size.
7.0–8.5pH
6–20GH (dGH)
72–82°FTemperature
1.5 inMax Size
Appearance & Colour
The Neon Blue Dorsal Stripe
Electric neon blue dorsal stripe running the full length of the body -- the most intensely coloured element of the species. The dorsal stripe of P. cyanodorsalis is a vivid, almost fluorescent blue that runs from behind the head to the base of the tail along the top of the body. In good lighting the stripe appears to glow, catching and reflecting light in a way that makes it visible from across the tank. The intensity of the blue is most pronounced in males and is most vivid in slightly alkaline water with moderate hardness.
Semi-transparent body with silver and pale yellow tones. Beneath the dorsal stripe the body is semi-transparent with subtle silver and yellow iridescence. The transparency of the body allows the vivid dorsal stripe to read as a distinct floating band of colour rather than a marking on an opaque surface, which contributes to the neon effect. Adult males also develop elongated fin extensions that add further visual complexity during display.
Keep in groups of 8 or more -- displaying behaviour requires a social group. Like all Pseudomugil species, P. cyanodorsalis is a shoaling fish that becomes timid and pale in small numbers. A group of 8 or more produces confident behaviour, active displaying between males, and the full colour expression the species is capable of. Maintain more females than males to reduce the intensity of male competition.
Shrimp Compatibility
Ideal for Neocaridina Tanks
Prefers harder, more alkaline water than most Pseudomugil -- aligns naturally with Neocaridina parameters. While most Pseudomugil species prefer soft, acidic water that suits Caridina tanks, P. cyanodorsalis naturally inhabits coastal waters with higher hardness and pH. Standard Neocaridina parameters (pH 6.8 to 7.8, GH 6 to 14) are ideal for this species, making it one of the most parameter-compatible Pseudomugil options for a Neocaridina setup without any water chemistry compromise.
Tiny mouth -- adult shrimp are completely safe. P. cyanodorsalis has a very small mouth and poses no threat to adult Neocaridina or Caridina shrimp. Newly hatched shrimplets in their first few days are the only size at any risk. In a planted tank with moss cover shrimplet survival alongside this species is very high. One of the most genuinely shrimp-safe fish in the hobby.
Do not mix with other Pseudomugil species if breeding is a goal -- hybridisation is possible. P. cyanodorsalis can hybridise with other Pseudomugil species if kept together. Maintain as a species-specific group or with non-Pseudomugil tankmates if breeding true is a priority.
Keeper's NoteThe Neon Blue-Eye is the most Neocaridina-compatible Pseudomugil species available because it prefers the same harder, more alkaline water that Neocaridina thrive in. A group of 10 in a 20-gallon planted Neocaridina tank on dark substrate with Java Moss and Rotala in the background produces a display where the neon blue dorsal stripe of the fish reads as a vivid horizontal accent moving through the upper water above the warm-coloured shrimp below. Feed small foods twice daily, maintain stable parameters, and this species is one of the most rewarding and most problem-free fish you can add to a shrimp tank.
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