Regal rainbowfish - Melanotaenia trifasciata

Scientific name: Melanotaenia trifasciata

Common name: Regal rainbowfish

Family: Melanotaeniidae

Usual size in fish tanks: 10 - 11 cm (3.94 - 4.33 inch)

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Recommended pH range: 7 - 8

Recommended water hardness: 8 - 18°N (142.86 - 321.43ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 24 - 30 °C (75.2 - 86°F)

The way how these fish reproduce: Spawning

Where the species comes from: Oceania

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Middle levels

Short description

The Regal rainbowfish (Melanotaenia trifasciata) is a vibrant Australian rainbow distinguished by its deep body and shimmering, multi-band coloration. It’s a peaceful but very active shoaler that thrives in clean, well-oxygenated water and looks best when kept in groups of 6 individuals in a long aquarium with open swimming lanes.

Origin

Oceania — native to Northern Australia (clear streams, rivers, floodplains). Habitats often have aquatic vegetation, submerged wood, and moderate current with highly oxygenated water.

Food and feeding

An omnivore that accepts quality flakes or micro-pellets as a staple. For color and condition, supplement with small live/frozen foods (baby brine shrimp, daphnia, cyclops, bloodworms) 3–4× weekly. Occasional blanched greens (spinach, zucchini) support gut health. Feed small portions twice daily to avoid waste.

Sexing

Males are typically larger and more intensely colored with a noticeably arched back; females remain slimmer and paler.

Breeding

A typical rainbowfish egg-scatterer. Provide fine-leaved plants or spawning mops. Eggs are adhesive and laid over several days. Parents may consume eggs—either remove adults or move the mops to a rearing tank. At 24–26 °C, eggs hatch in about 7–10 days. Start fry on infusoria/rotifers, transitioning to newly hatched brine shrimp as they grow. Maintain immaculate water; growth is steady but not fast.

Lifespan

Typically 5–8 years with stable, low-nitrate water and varied feeding.

Tank requirements

Tank size: minimum ~150 L (40 gal) for a small group; longer tanks preferred.
Aquascape: open swimming space with plants at back/sides, wood/rock for structure, and some shaded areas.
Water: pH 7–8, hardness 8–18°dH; temperature 24–30 °C. Keep oxygen high and nitrate low.
Flow & filtration: moderate current; robust bio-mechanical filtration; consistent weekly water changes.

Care tips for Regal rainbowfish

Keep in groups (6 ) to reduce stress and enhance coloration/display.
Provide a long tank with clear swimming lanes; avoid cramped quarters.
Use high oxygen and steady flow—these fish come from well-aerated waters.
Feed a varied diet (quality pellets small live/frozen foods) for best condition.
If breeding is a goal, avoid mixing with other Melanotaenia species to prevent hybridization.

Tankmates

Excellent with other peaceful, medium-sized fish of similar activity (other rainbowfish of the same species/locale, larger rasboras, peaceful gouramis, Corydoras). Avoid nippy species and very small or very slow fish that may be stressed by their activity level.

Short description (summary)

A hardy, colorful shoaling fish that rewards good husbandry with spectacular displays. Provide space, oxygen, and clean water, and keep them in groups to see their best behavior and color.