Beautiful fish from Australia/New Guinea that shine rainbow colors in morning light. Spectacular in schools.
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属性
Rainbowfish belong to the family Melanotaeniidae and are native to the rivers and lakes of Australia and New Guinea, where they inhabit slow-moving, often heavily vegetated waters. First brought to the attention of Western aquarists and scientists in the late 1800s, they have since become a staple of the freshwater hobby worldwide. Depending on the species, adults range from 5 to 15 cm, with males typically displaying a more diamond-shaped body profile and far more vivid coloration than females, especially when competing for mates. Their peaceful, sociable nature makes them ideal for community aquariums, and a school of six or more swimming together under good lighting is a genuinely spectacular sight. They prefer slightly alkaline, clean water and reward their keeper with the best colors when water quality is consistently maintained. Hardy enough for beginners yet visually rewarding enough for experienced aquarists, rainbowfish occupy a unique place in the hobby that few other species can match.
1Tank Size Guide
Adults reach 5–15 cm depending on species, so a 60 cm or larger tank is recommended when keeping a school. They are active swimmers that use horizontal space freely, making wider tanks preferable. Allow roughly 10 L per fish to prevent overcrowding and water quality issues.
2Water Conditions
They thrive at pH 7.0–8.0 and 24–28 °C. Sudden temperature swings or acidic water can stress them, so reliable heating and filtration are essential. Weekly partial water changes of around one-third of the tank volume help maintain stable conditions.
3Schooling Behavior
Rainbowfish feel secure in groups and display their best colors when kept in schools. Solitary or small-group keeping can make them shy and dull their coloration. A minimum of 5–6 individuals of the same species encourages natural behavior and vibrant nuptial coloring.
4Compatibility Tips
They are peaceful and compatible with most mid-sized community fish, but avoid fin-nippers such as tiger barbs or certain angelfish. Similarly sized, gentle species generally coexist well. Mixing different rainbowfish species is also an attractive option that works in most cases.
5Feeding Habits
They accept dry flake or pellet food readily, but supplementing with frozen bloodworms or brine shrimp several times a week supports vibrant coloration and overall health. Their mouths are relatively small, so finely crushed flakes or small pellets work best. Feed twice daily in amounts consumed within 3–5 minutes.
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6Sexing and Breeding
Males display more vivid coloration and tend to have larger, more developed fins than females. Breeding is relatively straightforward; they scatter eggs among plants or fine-leaved vegetation. As adults may eat their own eggs, moving the eggs to a separate tank after spawning significantly improves hatch rates.
7Cost Considerations
Prices per fish vary by species and availability, but common varieties typically range from a few hundred to a few thousand yen. Initial setup costs—tank, filter, heater, and lighting—run roughly 10,000–20,000 yen for a starter kit or 30,000–50,000 yen for a 60 cm setup. Ongoing monthly expenses for food, electricity, and consumables generally fall in the 500–1,000 yen range.