Spotted Blue-Eye Rainbowfish (Pseudomugil Gertrudae)

*Note: Images are used as an example only. Due to the nature of live animals, colouration, size and patterns may vary.*

Spotted Blue-Eye Rainbowfish
Scientific Name: Pseudomugil gertrudae
(Also known as the Gertrude’s Blue-Eye or Dwarf Spotted Rainbowfish.)

Overview
The Spotted Blue-Eye Rainbowfish is a delicate, beautifully patterned nano species known for its striking black body spots, translucent fins, and vivid blue eyes. These lively, fluttering swimmers add elegance and activity to planted aquariums. Although small and peaceful, they show their best colours and behaviour in well-planted, stable environments with gentle water flow and a supportive group structure.

Key Features

• Distinct black spots across the body and fins
• Bright blue irises that shimmer under aquarium lighting
• Lively, fluttering swimming style unique to Pseudomugil species
• Peaceful nano fish ideal for planted aquariums
• Displays natural courtship dances when kept in groups

Care Level: Easy to Moderate
Hardy when kept in stable, mature tanks; appreciates good water quality, gentle flow, and secure planting.

Habitat Requirements
Environment Type: Freshwater
Tank Size: Best results in 40+ litres; can be kept in 25 litres with excellent maintenance and a proper group size
Temperature: Ideally 24–28°C; tolerates 22–30°C
Water Parameters: pH 6.5–7.5 preferred; stable 6.0–8.0 acceptable
Water Hardness: Soft to moderately hard water
Water Flow: Gentle to moderate, avoiding strong currents
Aquascape: Dense planting, floating plants, and shaded areas help them feel secure; open spaces are needed for group swimming and displays

Diet
Primary Diet: High-quality micro pellets, nano granules, or crushed flakes
Variety: Frozen or live foods such as baby brine shrimp, daphnia, cyclops, and micro-worms help maintain health and colour
Flexible Options: Will pick at small natural foods in mature aquariums
Feeding Frequency: Small meals 1–2 times per day

Compatibility
Tank Mates: Peaceful nano fish such as rasboras, small tetras, pygmy Corydoras, and shrimp
Avoid: Large, fast, or aggressive species that may outcompete or intimidate them
Temperament: Peaceful but active; males display fluttering courtship dances

Size and Lifespan
Adult Size: 3–4 cm
Typical Lifespan: 3–5 years with consistent care

Behaviour and Activity
Spotted Blue-Eye Rainbowfish are lively shoaling fish with a distinctive, flickering swimming style. Males frequently perform small, rapid courtship displays, especially when kept in groups with plenty of space and cover. They are most confident and colourful in well-planted aquariums.

Special Requirements or Considerations
A mature aquarium with stable water quality brings out their best condition. Keeping them in groups of at least six is recommended to encourage natural displays and reduce stress. Covering the tank is advised, as they can be capable jumpers.

Ideal For

• Planted and heavily aquascaped aquariums
• Nano and peaceful community setups
• Aquarists seeking active, elegant schooling behaviour
• Keepers who appreciate subtle colours and natural displays

Additional Notes
Spotted Blue-Eye Rainbowfish thrive when given stable, warm water, gentle flow, and a varied diet of suitably small foods. While adaptable within reason, optimal care enhances their colour, activity, and captivating display behaviours.