Product Details

Goldie River Rainbow – Melanotaenia cf. goldiei “Dekai”

The Goldie River Rainbow is a larger, active rainbowfish with strong colour potential, confident shoaling behaviour and a distinctive locality-based trade identity. This Dekai form is best listed as Melanotaenia cf. goldiei “Dekai”, as it is associated with the Goldie River Rainbowfish group but may represent a locality or collection form rather than a fully confirmed standard aquarium strain. It is best suited to spacious, mature aquariums with clean, well-oxygenated water, open swimming space and a proper group.

Key Identification:

Common Name: Goldie River Rainbow
Other Names: Goldie River Rainbowfish, Goldiei Rainbowfish, Dekai Rainbowfish, Goldie’s Rainbowfish
Scientific Name: Melanotaenia cf. goldiei “Dekai”
Older / Trade Name: Melanotaenia goldiei “Dekai”
Locality / Strain: Dekai
Fish Type: Rainbowfish
Water Type: Freshwater

Natural Range & Habitat:

Melanotaenia goldiei is a New Guinea rainbowfish associated with a range of freshwater habitats, including swamps, backwaters, tributary streams and larger river systems. These environments can include areas of vegetation, submerged wood, open swimming space and seasonally variable water conditions.

The Dekai form should be treated as a locality or collection strain. In the aquarium, it should be provided with a spacious planted or natural-style setup with open swimming areas, plants around the edges, good filtration and stable water quality.

Appearance & Adult Size:

Goldie River Rainbows are medium to larger rainbowfish with a streamlined body, strong swimming ability and developing adult colour that improves with maturity. Males may show blue, green, yellow, orange or reddish tones depending on locality, condition, mood and lighting, often with stronger fin colour and body depth as they age.

Females are usually smaller, slimmer and less intensely coloured, though still attractive in a settled group. Adults commonly reach around 10–12 cm, with older males becoming deeper-bodied and more impressive over time.

Aquarium Suitability:

This species is well suited to larger planted community aquariums, rainbowfish displays and New Guinea-style setups. It needs open swimming space, a secure group, clean water and peaceful but robust tank mates.

Goldie River Rainbows are generally hardy once settled, but they are active fish and should not be kept in cramped aquariums. Juveniles may appear comparatively plain, but males develop stronger colour and body shape with age, good food and stable conditions.

Recommended Aquarium Size:

A practical minimum is 200 litres for a group, with a tank length of at least 120 cm recommended. Larger aquariums are strongly preferred for mature adults and mixed rainbowfish displays.

Keep in a group of at least 6, with 8 or more preferred where space allows. A mixed group with both males and females encourages better colour, natural display behaviour and more stable social interaction.

Water Conditions:

Temperature: 24–28°C
pH: 7.0–8.0
Hardness: Moderately soft to moderately hard
Additional Notes: Goldie River Rainbows prefer clean, stable, well-oxygenated water with regular water changes. They are adaptable, but they do best in mature aquariums with good filtration and plenty of swimming room. Avoid poor water quality, low oxygen, unstable new aquariums and cramped conditions.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Goldie River Rainbows are peaceful, active shoaling fish. Males may display and chase lightly, but this is usually normal rainbowfish behaviour when the group is large enough and space is adequate.

Suitable tank mates include other similar-sized rainbowfish, peaceful barbs, larger rasboras, robust tetras, livebearers in suitable water, peaceful bottom-dwelling catfish and other calm medium-sized community fish. Avoid large predators, aggressive cichlids, fin-nippers and very small shy fish that may be intimidated by their activity.

Feeding:

Goldie River Rainbows are omnivorous and easy to feed once settled. Offer quality flakes, small to medium pellets and granules as the staple diet.

Supplement with frozen or live foods such as daphnia, brineshrimp, cyclops, mosquito larvae and bloodworm. Vegetable and algae-based foods can also be included. A varied diet helps support colour, growth, breeding condition and long-term health.

Behaviour in the Aquarium:

This is an active midwater shoaling fish that spends much of its time swimming in open areas. Males may display to females and rival males by intensifying colour, spreading fins and swimming side by side.

Breeding may occur in mature aquariums. Like other rainbowfish, they scatter adhesive eggs among fine-leaved plants, moss or spawning mops over a period of days. Adults may eat eggs or fry, so separate breeding arrangements are needed if you want to raise young.

Care Notes:

Provide a spacious aquarium with open swimming room, good filtration and stable water quality. This is not a nano rainbowfish and should be planned for as a larger, active species.

Keep in a proper group and avoid mixing different Melanotaenia goldiei locality forms if maintaining strain purity is important. Colour improves with age, diet, space and low stress, so young fish should be given time to mature. A secure lid is recommended, as active rainbowfish can jump when startled.

Recommended For:

Beginner to intermediate

Availability:

Rare to occasional / Specialist rainbowfish strain or locality form

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, colour, pattern, fin shape, body tone and markings can occur between individual fish.