Product Details

Blyth River Banded Rainbowfish – Melanotaenia trifasciata “Blyth River”

Overview:

The Blyth River Banded Rainbowfish is a bold, active Australian rainbowfish with the deep body, dark central stripe and colourful mature males that make Melanotaenia trifasciata so popular. This Blyth River locality form is especially valued by rainbowfish keepers who want a genuine strain with strong display behaviour and a natural wild-type look. It is a peaceful shoaling fish, but it needs a long, spacious aquarium, clean water and a proper group to show its best colour.

Key Identification:

Common Name: Blyth River Banded Rainbowfish
Other Names: Blyth River Rainbowfish, Three Stripe Rainbowfish, Banded Rainbowfish, Jewel Rainbowfish, Three-striped Sunfish
Scientific Name: Melanotaenia trifasciata “Blyth River”
Fish Type: Rainbowfish
Water Type: Freshwater

Natural Range & Habitat:

The wider species, Melanotaenia trifasciata, is native to northern Australia, where it occurs in small streams, creeks and waterholes, often in clear to moderately turbid water over rocky, gravelly or vegetated areas with submerged logs and branches. FishBase also records the species from semi-rainforest and open grassland habitats, with seasonal waterholes sometimes containing leaf litter during the dry season.

The Blyth River strain comes from the upper Blyth River area in Arnhem Land, Northern Territory. AquaGreen records broodstock habitat as a small spring-fed stream, with fish collected from faster, shaded water; dry-season measurements included around 27°C, pH 7.6, carbonate hardness 100 ppm and hardness 90 ppm.

Appearance & Adult Size:

Blyth River Banded Rainbowfish have a deep, laterally compressed body with a strong dark horizontal stripe running through the middle of the flank. Mature males develop the best colour, often showing metallic body tones with red, orange or yellow highlights in the fins, while females and young fish are usually slimmer and more subdued. Fishes of Australia describes M. trifasciata as a variable species with greenish to bluish upper body tones, a dark midlateral stripe and yellowish to bright red dorsal, anal and caudal fins.

Adults commonly reach around 10–12 cm, with large males becoming deeper-bodied as they mature. FishBase lists M. trifasciata at up to around 12 cm standard length, so it should be planned as a medium-sized, active shoaling fish rather than a small community species.

Aquarium Suitability:

This is an excellent fish for a larger planted aquarium, Australian-style display or mixed rainbowfish community. It needs open midwater swimming space, good filtration and a layout that allows the group to move freely. Planting around the back and sides works well, especially with clear swimming lanes through the centre.

Blyth River Banded Rainbowfish are too active for small aquariums or cramped aquascapes. They are also not ideal with very shy, slow or delicate fish that may be unsettled by fast feeding and constant movement.

Recommended Aquarium Size:

A practical minimum is 240 litres for a group, with a tank length of at least 120 cm recommended. Larger aquariums are preferred for adult males, larger shoals or mixed rainbowfish groups.

Water Conditions:

Temperature: 22–28°C
pH: 6.8–7.8
Hardness: Moderately hard preferred; adaptable if stable
Additional Notes: Provide clean, well-oxygenated water with regular water changes and gentle to moderate flow. FishBase gives a broad range of 22–30°C and pH 5.2–7.0 for the species, while the Blyth River broodstock locality data records slightly alkaline water at pH 7.6. Stability and good maintenance are more important than chasing one exact number.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Blyth River Banded Rainbowfish are peaceful, confident shoaling fish. Suitable tank mates include other rainbowfish, larger tetras, danios, peaceful barbs, robust rasboras, Cory-type catfish, bristlenose plecs, peaceful loaches and calm medium-sized cichlids that enjoy similar water conditions.

Avoid aggressive cichlids, fin-nippers, very tiny fish and slow, delicate species that may be intimidated at feeding time. Keep in a group of at least 6, with 8 or more strongly preferred. A mixed-sex group is best, as males usually show stronger colour and more display behaviour when females and rival males are present.

Feeding:

Blyth River Banded Rainbowfish are easy-feeding omnivores. Offer quality flakes, small granules and rainbowfish pellets as the staple diet, with regular frozen or live foods such as daphnia, brineshrimp, cyclops, bloodworm and mosquito larvae. Include some vegetable or algae-based foods for balance. Feed small portions that are eaten quickly, as rainbowfish are fast and enthusiastic feeders.

Behaviour in the Aquarium:

This species spends much of its time in the middle and upper levels, cruising in a loose group. Mature males may intensify their colour, raise their fins and display to one another, especially in the morning, after water changes or when females are nearby. They are active but not usually aggressive, making them best suited to confident community fish with similar energy levels.

Care Notes:

Keep in a mature aquarium with stable water quality, strong filtration and a secure lid, as rainbowfish can jump when startled. Do not keep singly or in pairs, as small numbers can become nervous and less colourful. Locality strains such as Blyth River should not be mixed with other Melanotaenia trifasciata localities if breeding may occur, as this can blur or lose the strain identity. Young fish may arrive with modest colour, but males improve greatly with age, diet and group structure.

Recommended For:

Beginner to intermediate

Availability:

Occasional / Specialist rainbowfish strain / 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, colour, pattern and markings can occur between individual fish.