Spotted Blue Eye Rainbowfish

Pseudomugil gertrudae

Animalia›Chordata›Actinopterygii›Pseudomugilidae

📍 Northern Australia and New Guinea

A tiny jewel of a fish, the spotted blue eye has vivid spotted fins and stunning iridescent blue eyes. Males display spectacular finnage with yellow and black markings during courtship. At just 3–4 cm (1.2–1.6 in) it is ideal for nano tanks and looks magnificent in a heavily planted setup. It prefers soft, slightly acidic to neutral water.

Size1.5"

Min Tank10g

School6+

peaceful

Zonemid

Care Guide

Diet

Spotted blue eyes are micro predators requiring small, live or frozen foods. Offer baby brine shrimp, micro worms, and daphnia once daily in small portions. High-quality micro pellets can supplement live foods, but live prey should comprise the majority of their diet for optimal coloration and health.

Behavior

These are active, peaceful schooling fish that display best behavior in groups of 8 or more. Males exhibit spectacular courtship displays with extended fins showing yellow and black markings, particularly in heavily planted tanks. They are mid-water swimmers that prefer calm environments and may become stressed or lose coloration if kept in isolation or with aggressive tankmates.

Breeding

Breeding in captivity is possible but requires patience and specific conditions. Provide dense vegetation (Java moss, Riccia) for egg scattering, soft acidic water (pH 6.0–6.5), and temperatures around 26–28°C. Fry are extremely small and require infusoria or liquid fry food initially; remove adults after spawning to prevent predation.

Tank Mates

Least Killifish

Similar size, peaceful temperament, and compatible water parameters make them ideal companions

excellent

Red Cherry Shrimp

Small shrimp won't compete for food and add biological diversity; thrive in same soft, slightly acidic water

excellent

Otocinclus

Peaceful algae eaters that occupy different tank zones and prefer similar water conditions

good

Dwarf Hairgrass

Foreground plant that creates ideal habitat structure and provides cover for fry if breeding

excellent

Java Moss

Essential for breeding and provides grazing surfaces for infusoria; creates natural aesthetic they prefer

excellent

Ramshorn Snail

Peaceful scavenger that maintains water quality without competing for micro foods

good

Common Diseases

Ich (White Spot Disease)

Symptoms

White spots on body and fins, rapid breathing, lethargy, flashing against plants

Treatment

Raise temperature gradually to 28–30°C, perform daily 25% water changes, use aquarium salt (1 tsp per 5 gallons) or ich medication; treat for 10–14 days

Fin Rot

Symptoms

Frayed or deteriorating fin edges, discoloration at fin bases, reduced activity

Treatment

Improve water quality with frequent partial changes, remove decaying plants, use antibacterial medication if severe; ensure good filtration and avoid overcrowding

Bacterial Infection

Symptoms

Cloudy eyes, open sores, loss of appetite, color fading, erratic swimming

Treatment

Perform 50% water change immediately, treat with broad-spectrum antibiotic medication, isolate affected fish if possible, maintain pristine water conditions

Stress-Related Color Loss

Symptoms

Fading of iridescent blue eye coloration, pale body color, reduced finnage display

Treatment

Increase school size to minimum 8 fish, add dense vegetation for security, reduce tank disturbances, ensure stable water parameters and appropriate feeding