The short answer
Rainbowfish are the most overlooked great fish in the hobby — and they are almost purpose-built for the UAE. They come from hard, alkaline waters, so Dubai tap suits them perfectly; they are hardy, peaceful and active; and the adults are spectacular. The catch is that they look drab and silver as juveniles in the shop, so beginners walk straight past them. Buy a small group, grow them on, and they colour up into some of the most beautiful fish you can keep.
| Rainbowfish | Size | Why keep it |
|---|---|---|
| Boesemani | ~10 cm | The famous one — half orange, half blue |
| Dwarf neon | ~6 cm | Small, electric blue; suits smaller tanks |
| Red (Glossolepis) | ~11 cm | Males a deep glowing red |
| Turquoise (Lake Kutubu) | ~11 cm | Shimmering blue-green, very peaceful |
The fish everyone walks past
Here is the single most useful thing to know about rainbowfish: the juveniles in the shop tank look like nothing. Small, silvery, colourless — next to a tank of flashy dwarf gouramis or fancy guppies, they are easy to ignore. So people do.
That is the mistake. Rainbowfish develop their colour as they mature, settle in and gain confidence, and a grown male displaying to his group is a shifting neon of orange, blue, red or green that few community fish can match. The lesson is simply to buy for the adult, not the juvenile — the same principle as picking a healthy fish, applied to colour. Choose a small group of healthy young fish, give them a settled tank and good food, and be patient. The pay-off is weeks away, not instant.
Rainbowfish love UAE hard water
Most rainbowfish come from the hard, alkaline waters of Australia, New Guinea and Indonesia. In other words, the water that troubles a neon tetra is the water they evolved in. For a UAE keeper that is a gift: no RO, no buffers, no treadmill — just dechlorinated tap water and a rainbowfish is at home, exactly the "stop fighting the water" logic in is Dubai tap water safe for fish.
It makes them one of the best-matched schooling fish for the region, right alongside the hardy end of the hard-water tetras. If you want a shoal that positively thrives in Dubai water rather than merely tolerating it, this is it.
The rainbowfish worth keeping
"Rainbowfish" covers a big family, from hand-sized showpieces to nano gems. The ones you will actually find, and want:
| Species | What to know |
|---|---|
| Boesemani | The iconic rainbowfish — a startling orange rear and blue front. Needs a decent-length tank; stunning in a group |
| Dwarf neon (praecox) | Only ~6 cm, electric blue with red fins. The rainbowfish for a smaller community |
| Red (Glossolepis incisus) | Dominant males turn a deep, glowing red. Large and active |
| Turquoise (Lake Kutubu) | A serene blue-green, and among the most peaceful of the bigger rainbows |
| Threadfin | A delicate nano rainbowfish with fabulous fins — beautiful, but more demanding and best in a calm species tank |
For most people: dwarf neon for a tank under about 100 litres, and boesemani, red or turquoise for anything larger where they have room to swim.
Space and schooling: give them room to run
Rainbowfish are fast, restless, active swimmers — that motion is half their appeal, and it drives their main requirement: swimming length. A short, tall tank frustrates them. The standard-size species (boesemani, red, turquoise) want a tank with real horizontal run, which is worth planning against your space using the best tank size for a Dubai apartment.
| Rainbowfish | Adult size | Sensible minimum tank |
|---|---|---|
| Dwarf neon | ~6 cm | ~75–100 L |
| Boesemani / red / turquoise | ~10–11 cm | 150 L+, and long rather than tall |
| Threadfin | ~4 cm | A calm nano species tank |
- Keep them in groups of six or more. They are schooling fish; in a group the males display and colour up, competing for attention. Singly or in pairs they are duller and edgier.
- A mixed-sex group is best. Males intensify their colour showing off to females and sparring bloodlessly with rival males — all display, no damage.
- Match size to tank. Dwarf neon for small tanks; save the big rainbows for tanks with length.
Feeding for colour
Rainbowfish are omnivores with surprisingly small mouths, so they do best on small foods: a quality flake or micro-pellet as the staple, plus frozen treats like daphnia, brine shrimp and bloodworms. Varied, colour-enhancing food genuinely matters here — good feeding is a big part of how those adult colours develop and hold. They are fast, greedy feeders, so make sure slower tankmates still get their share.
Tankmates
An active, peaceful rainbowfish shoal sits at the heart of a lively community. They are not nippers and not aggressive, but their speed and appetite mean they suit other robust, active fish rather than shy slowpokes:
- Great with: other rainbowfish, larger hardy tetras, peaceful active barbs, corydoras, and calm centrepieces like a pearl gourami.
- Fine with a centrepiece: they are too big and too fast to be an angelfish's dinner, unlike small tetras.
- Less ideal with: very shy, slow or long-finned fish that get out-competed at feeding time.
Build the community around them with the stocking plan and check any new fish against the compatibility guide. If you want a second, smaller school lower in the water, pair them with peaceful rasboras.
Frequently asked questions
Why are my rainbowfish not colourful?
Almost always because they are young, unsettled, or kept in too small a group. Rainbowfish develop their colour as they mature in a stable tank, and males intensify it displaying within a group. Give them time, a group of six or more, good food and a settled tank, and the colour comes.
Are rainbowfish good for hard water?
They are excellent for it. Most rainbowfish come from hard, alkaline waters, so UAE tap suits them perfectly — no RO or special treatment needed. They are one of the best-matched schooling fish for Dubai water.
How many rainbowfish should I keep?
Six is the minimum; more is better. They are schooling fish that are calmer, bolder and far more colourful in a group, ideally a mixed-sex one where the males display. Small groups look drab and can be nervous.
What size tank do rainbowfish need?
It depends on the species. The dwarf neon rainbowfish is happy in a tank under 100 litres, but the standard boesemani, red and turquoise types are active swimmers that need a longer tank with real horizontal swimming room.
Are rainbowfish peaceful?
Yes. They are peaceful, non-nipping community fish. They are simply fast and active, so they suit other robust, active tankmates better than very shy or slow ones. Male-to-male sparring is display, not damage.
What do rainbowfish eat?
They are omnivores with small mouths, so feed small foods: a quality flake or micro-pellet staple plus frozen daphnia, brine shrimp and bloodworms. Varied, colour-enhancing food helps their adult colours develop fully.
The short version
- Rainbowfish are hardy, peaceful, active schoolers that love UAE hard water — no RO needed.
- They look drab as juveniles and stunning as adults; buy young and grow them on.
- Best picks: dwarf neon for smaller tanks; boesemani, red or turquoise for larger ones.
- Keep six or more, ideally mixed-sex, so males colour up and display.
- Give the standard species swimming length, not just volume.
- Feed small, varied, colour-enhancing food; they are fast eaters.
- Great with other active community fish, and too big to be a centrepiece's snack.
A rainbowfish shoal is the active upper layer of a community. For a calmer, smaller school to fill the middle and lower water, the natural partner is the rasbora — the quiet counterpoint to the rainbowfish's flash.