Product Details

Emerald Green Rainbowfish – Glossolepis wanamensis

The Emerald Green Rainbowfish is a rare and beautiful New Guinea rainbowfish known for its shimmering green, blue-green and metallic body colour. Also called the Lake Wanam Rainbowfish, Glossolepis wanamensis is an active, peaceful shoaling fish best suited to spacious planted aquariums with clean, stable water and plenty of swimming room. Because this species is conservation-sensitive, captive-bred stock and responsible line keeping are especially important.

Key Identification:

Common Name: Emerald Green Rainbowfish
Other Names: Lake Wanam Rainbowfish, Emerald Rainbowfish, Wanam Rainbowfish
Scientific Name: Glossolepis wanamensis
Fish Type: Rainbowfish / Melanotaeniid
Water Type: Freshwater

Natural Range & Habitat:

Glossolepis wanamensis is endemic to Lake Wanam in Papua New Guinea. FishBase describes it as a lake species from a high-altitude lake around 150 m elevation, while other references describe Lake Wanam as a small lake west of Lae.

In the aquarium, Emerald Green Rainbowfish should be kept in a mature, well-filtered setup with open swimming space, planted edges, rockwork, wood and good oxygenation. They are active midwater fish, so the aquarium should not be overcrowded with décor.

Appearance & Adult Size:

Emerald Green Rainbowfish have a deep, laterally compressed rainbowfish body with a metallic green, blue-green, bronze or emerald sheen. Mature males usually show the strongest colour and deeper body shape, while females are generally smaller, slimmer and more subdued. Colour can vary with age, sex, mood, lighting, diet and breeding line.

Adults usually reach around 8–9 cm, making this a medium-sized rainbowfish that needs more room than small tetras or nano species.

Aquarium Suitability:

This species is best suited to larger peaceful community aquariums, planted rainbowfish displays and conservation-minded species setups. It suits aquariums with open midwater swimming lanes, plants around the sides and back, moderate water movement and excellent water quality.

Emerald Green Rainbowfish are not suitable for tiny aquariums, shy nano communities, aggressive cichlid tanks, predator aquariums or cramped layouts with little swimming room. They are peaceful, but their activity can intimidate very slow or delicate fish.

Recommended Aquarium Size:

A practical minimum is 180 litres for a group, with a tank length of at least 100 cm recommended. Larger aquariums of 240 litres or more are preferred for mature groups, mixed rainbowfish displays and better long-term colour development.

Keep in a group of at least 6, with 8 or more preferred. A mixed-sex group is ideal, as males show their best colour and display behaviour when females and rival males are present.

Water Conditions:

Temperature: 24–29°C
pH: 7.0–8.0
Hardness: Moderately hard preferred
Additional Notes: Keep water clean, stable and well oxygenated. This species appreciates regular partial water changes, strong biological filtration and steady mineral content. Avoid poor oxygenation, high nitrate, sudden water-chemistry changes and cramped, stagnant aquariums.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Emerald Green Rainbowfish are peaceful but active community fish. Suitable tank mates include other rainbowfish of similar size, larger peaceful tetras, danios, robust rasboras, peaceful barbs, Cory-type catfish in compatible temperatures, bristlenose plecs and other confident community species.

Avoid very small nano fish, shy slow feeders, long-finned delicate species, large predators and aggressive cichlids. Adult rainbowfish may eat very small fry or tiny shrimp, so they are not ideal for shrimp-breeding aquariums.

Feeding:

Emerald Green Rainbowfish are easy-feeding omnivores. Offer quality flakes, small floating or slow-sinking granules and rainbowfish pellets as the staple diet. Supplement with frozen or live foods such as daphnia, cyclops, brineshrimp, mosquito larvae, bloodworm and small insect-based foods.

A varied diet supports colour, body condition and display behaviour. Feed small amounts that are eaten quickly, as active rainbowfish have strong appetites and do best with clean water.

Behaviour in the Aquarium:

This is an active midwater swimmer that spends much of the day moving through open areas of the aquarium. Males may display to females and rival males by intensifying colour, flaring fins and making short chasing movements. This is normal in a suitable group and usually does not cause harm when there is enough space.

Emerald Green Rainbowfish are egg scatterers. Females deposit adhesive eggs among fine plants, mosses or spawning mops, and adults do not provide parental care. Fry require separate rearing if breeding is intended.

Care Notes:

Add Emerald Green Rainbowfish only to a mature, fully cycled aquarium. Provide open swimming room, stable water quality and a secure lid, as active rainbowfish can jump when startled. Avoid overcrowding, poor oxygenation and long periods without water changes.

Do not mix locality strains or closely related rainbowfish if breeding for conservation or line purity. This species is best sourced from responsible captive-bred lines, and any breeding groups should be maintained carefully.

Recommended For:

Intermediate

Availability:

Occasional / Specialist captive-bred conservation-sensitive species

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, emerald colour, metallic sheen, fin length, sex, age and markings can occur between individual fish.

Fish Label Key Stats: