Product Details

potted Blue-Eye Rainbowfish – Pseudomugil gertrudae “Aru IV”

The Spotted Blue-Eye Rainbowfish is a small, elegant blue-eye with bright blue eyes, delicate spotted fins and lively display behaviour. This Aru IV form of Pseudomugil gertrudae is a locality strain, making it especially appealing for aquarists who enjoy keeping distinctive rainbowfish lines. It is peaceful, active and colourful, but it should be kept in a mature aquarium with gentle tank mates, stable water quality and plenty of plant cover.

Key Identification:

Common Name: Spotted Blue-Eye Rainbowfish
Other Names: Spotted Blue-Eye, Gertrude’s Blue-Eye, Blue-Eye Rainbowfish, Aru IV Spotted Blue-Eye
Scientific Name: Pseudomugil gertrudae “Aru IV”
Fish Type: Blue-Eye / Rainbowfish Relative
Water Type: Freshwater

Natural Range & Habitat:

Pseudomugil gertrudae is found across northern Australia, southern New Guinea and the Aru Islands. The Aru IV form is a locality strain associated with the Aru Islands, and should be treated as a distinct line in the aquarium hobby.

In the wild, Spotted Blue-Eyes inhabit quiet creeks, swampy marshes, shaded rainforest streams, lily lagoons and vegetated backwaters. They are often associated with dense aquatic vegetation, submerged debris, shallow margins and calm water rather than strong open current.

In the aquarium, they do best in mature planted setups with fine-leaved plants, mosses, floating plants, wood, gentle flow and open areas for displaying.

Appearance & Adult Size:

Spotted Blue-Eyes are small, slender fish with bright blue eyes and beautifully patterned fins. Males are the showiest, often displaying yellow, orange, black and white fin markings with fine spots and extended fin rays. Females are smaller and more subdued, but still attractive in a group.

Adults usually reach around 3–4 cm, making them suitable for smaller planted aquariums when kept with peaceful tank mates. The best colour is usually seen in settled males displaying to females and rival males.

Aquarium Suitability:

This species is best suited to mature planted aquariums, nano-to-small community tanks and specialist blue-eye or rainbowfish displays. It needs clean water, calm tank mates and a layout with plant cover as well as swimming space.

Spotted Blue-Eyes are not suitable for aggressive communities, predator tanks, boisterous barbs, large cichlids, very strong-flow river tanks or aquariums with fish large enough to swallow them.

Recommended Aquarium Size:

A practical minimum is 45–60 litres for a small group, with a tank length of at least 45–60 cm recommended. Larger aquariums are preferred for bigger groups, mixed-sex displays and more stable water quality.

Keep in a group of at least 8, with 10 or more preferred. A mixed-sex group gives the best display behaviour, as males show stronger colour and fin extension when displaying to females.

Water Conditions:

Temperature: 23–28°C
pH: 5.5–7.5
Hardness: Soft to moderately hard
Additional Notes: Stable, clean water is more important than chasing exact numbers. Avoid sudden changes in temperature, pH or hardness. This species appreciates mature aquariums with plants, gentle flow and good oxygenation. Very hard, alkaline water is best avoided unless the fish are locally acclimated.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Spotted Blue-Eyes are peaceful community fish, but they are small and should be kept with gentle companions. Suitable tank mates include small rasboras, peaceful tetras, small Cory-type catfish, Otocinclus, small peaceful gobies, dwarf shrimp with caution, other peaceful blue-eyes and calm nano community fish.

Avoid large predators, aggressive cichlids, fin-nipping barbs, boisterous rainbowfish, large gouramis and any fish that may outcompete them at feeding time. Adult fish may eat very tiny shrimplets or fry, so they are not ideal for maximum shrimp breeding.

Feeding:

Spotted Blue-Eyes are small omnivores that need fine foods. Offer quality micro pellets, finely crushed flakes, small soft granules and powdered or micro-sized foods as the staple diet. Supplement with live or frozen foods such as baby brineshrimp, cyclops, daphnia, microworms and small mosquito larvae.

Small live and frozen foods are especially useful for conditioning males and improving display colour. Feed small portions that are eaten quickly, as they have small mouths and can be outcompeted by faster fish.

Behaviour in the Aquarium:

This species is active, social and often displays in open areas near plants. Males flare their fins, circle females and display to rival males, creating a lively but generally peaceful aquarium scene. They tend to use the middle and upper levels of the tank, especially around plant cover and shaded margins.

Spotted Blue-Eyes are egg scatterers. Females deposit adhesive eggs among fine plants, mosses or spawning mops, and adults do not provide parental care. Fry require very small first foods if breeding is intended.

Care Notes:

Add Spotted Blue-Eyes only to a mature, fully cycled aquarium. Provide floating plants, fine-leaved plants, gentle filtration and stable conditions. A secure lid is recommended, as small active fish can jump when startled.

Do not mix Aru IV with other Pseudomugil gertrudae locality strains if breeding for line purity. Keeping locality forms separate helps preserve their appearance and value within the hobby.

Recommended For:

Beginner to intermediate

Availability:

Occasional / Specialist rainbowfish strain, often captive-bred when available

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, blue eye intensity, fin spotting, fin colour, sex, age and markings can occur between individual fish.