Red Rainbowfish

Red Rainbowfish key facts

Care level

Intermediate

Lifespan

5-8 years

Size

12-15cm

Temperature

22〜25℃

Diet

Dried, frozen and live foods

Tank

Seriously Fish suggests a 120 x 30cm base of about 108 litres. It swims strongly, so choose a long tank and separate densely planted areas from open swimming space, keeping the flow gentle.

Water Temperature & Quality

Seriously Fish gives 22-25C, pH 7.0-8.0 and 10-20 dGH, and warns that the fish does poorly in soft, acidic conditions. FishBase records pH 7.6-8.2 and 9-19 dH in the wild.

Tank Mates

Peaceful but fast and fairly large, so it unsettles small or slow-moving fish. Similar-sized rainbowfish, characins, danios, barbs and Corydoras suit it. A shoal of six to eight or more settles it.

Diet & Feeding

It is unfussy and takes dried, frozen and live foods. Regular frozen and live feeds bring out the best colour.

Breeding & Spawning

Breeding is easy; it is an egg scatterer. Use a spawning tank at about pH 7.5 and 21-24C with java moss or spawning mops. The female attaches a few eggs by threads each day over several weeks, and the fry are best raised separately.

Health & Notes

The male's red develops with maturity, so young fish on sale look drab and are hard to judge. Degradation of Lake Sentani has led the IUCN to list the species as Endangered. It is not covered by CITES.

About Red Rainbowfish

A rainbowfish native to Lake Sentani, Papua. Mature males turn brilliant red with a tall arched back, coloring up best when kept in schools of six or more.

7 things to know before welcoming a Red Rainbowfish

1. 1Hard, Alkaline Water

   Red Rainbowfish thrive in hard, slightly alkaline water and can struggle in neutral-to-acidic conditions. Using coral sand or a mineral-rich substrate helps keep pH and hardness in the right range. Regular water testing helps you catch drift before it becomes a problem.

2. 2Keep Them in Groups

   Males show their best red coloring when kept in schools of six or more. Kept alone or in small numbers, they tend to color up less and can become shy or stressed. Plan for a tank large enough to support a proper school.

3. 3Color Develops With Age

   As males mature, their bodies develop a tall, arched back and deepen into vivid red. This transformation takes time, so fish sold young often still look relatively plain. Watching the color develop is part of the appeal of keeping this species.

4. 4Plan for Adult Size

   Adults reach 12–15 cm, so it's worth choosing a tank with their full grown size in mind, not just their size at purchase. Schooling groups especially need enough open swimming space. Give them room to grow rather than upgrading later.

5. 5Peaceful, Good Mixer

   Red Rainbowfish are generally peaceful and get along well with other similarly sized tropical fish. Pairing them with aggressive or fin-nipping species can lead to damaged fins, so choose calm tankmates. A community tank with other peaceful schooling fish works well.

6. 6Keep the Tank Covered

   Like other rainbowfish, they can jump when startled, so a secure lid is important. Be especially careful during water changes or maintenance when your hands are near the surface, as a sudden fright can send them leaping out.

7. 7Offer Some Plant Matter

   They're omnivorous and readily accept standard flake or pellet food, but mixing in plant-based options supports better overall health. This species is generally considered suited to intermediate keepers, so it helps to be comfortable with water quality management first.

Frequently asked questions about Red Rainbowfish

Q.Is this a good fish for beginners?

A.Red Rainbowfish are generally considered suited to intermediate keepers rather than complete beginners. They need attentive water chemistry management (hardness and pH), so it helps to have some tropical fish experience first. Once you're comfortable with water quality basics, they're a rewarding fish to keep.

Q.How big a tank do I need?

A.Adults grow to 12–15 cm, and since their coloring improves in groups, you'll want a tank with plenty of open swimming room. This matters even more if you're keeping a full school rather than just one or two fish.

Q.Do males and females look different?

A.Yes — mature males develop a striking overall red color along with a tall, arched back, which is their most distinctive feature. Females and younger fish tend to show much more subdued coloring.

Q.Can they live with other fish?

A.They're generally peaceful, so they do well alongside other calm, similarly sized tropical fish. It's best to avoid aggressive or very small tankmates that could clash with them.

Q.Is the Red Rainbowfish subject to CITES?

A.The Red Rainbowfish is not subject to CITES. It's a popular aquarium fish native to Lake Sentani in Indonesia's Papua region.

Useful tools for Red Rainbowfish care

Learn more about Red Rainbowfish in the encyclopedia

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