Pacific Blue-Eye Rainbowfish (Pseudomugil signifer)

Pacific Blue-Eye (Pseudomugil signifer) is a small, colorful rainbowfish native to eastern Australia. It is prized for its striking blue eyes, active schooling behavior, and suitability for planted community aquariums.

Quick Facts

• Scientific name: Pseudomugil signifer
• Common names: Pacific Blue-Eye, Pacific Blue-Eye Rainbowfish
• Origin: Coastal streams, swamps, estuaries, and mangrove habitats of eastern Australia. 
• Adult size: Typically 4-7.5 cm (1.5-3 in). 
• Temperature: 18-27°C (64-81°F). 
• pH: 6.5-7.5. 
• Temperament: Peaceful and community-friendly. 

Aquarium Care

Pacific Blue-Eyes prefer:

• Densely planted aquariums
• Floating plants for cover
• Well-oxygenated water
• Moderate water movement
• Mature, stable tanks with consistent water parameters. 

Because they are shoaling fish, they should be kept in groups of at least 6-10, with larger groups producing more natural behavior and better male display coloration. 

Feeding

They are omnivorous and readily accept:

• Quality flakes and micro-pellets
• Baby brine shrimp
• Daphnia
• Cyclops
• Small frozen foods and live foods. 

Compatibility

Excellent tankmates include:

• Other small rainbowfish
• Celestial Pearl Danios
• Ember Tetras
• Small rasboras
• Peaceful gobies and dwarf catfish. 

Avoid large predatory fish or fin-nippers. 

Notable Characteristics

• Brilliant electric-blue eyes
• Males develop elongated fins and brighter colors during courtship. 
• Can tolerate a range of salinities, from freshwater to brackish environments. 
• Forms loose schools in the wild, sometimes numbering hundreds or thousands of fish. 

For a planted nano or community aquarium, the Pacific Blue-Eye is one of the best small rainbowfish species available, combining vivid color, constant activity, and peaceful behavior.