Easy carePeacefulSchool of 6+Papua New Guinea

Turquoise Rainbowfish

Melanotaenia lacustris

The Turquoise Rainbowfish (Melanotaenia lacustris) is a peaceful fish that's easy to keep. Give it a tank of at least 180 litres (48 US gallons), water held at 75-82°F, and a pH of 6.5-8. Always keep a group of at least 6 - they feel safest in numbers.

Care levelEasy

TemperamentPeaceful

Min tank size48 US gal

pH range6.5-8

Temperature75-82°F

Max size4.7 in (12.0 cm)

Captive lifespan5-10 years

SchoolingYes · 6+ recommended

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

Papua New Guinea

Australia & Oceania

Regional colours match the stocking calculator's origin map.

Turquoise Rainbowfish Tank Setup

Give them a tank of at least 180 litres (48 US gallons). As open-water swimmers they care more about swimming length than height, so a longer tank is ideal. Keep the water at 75-82°F with a pH around 6.5-8, and avoid sudden swings. Always keep a group of at least 6 of their own kind - kept alone or in pairs they tend to turn shy, nippy, or wash out in colour. They reach about 12 cm as adults, so don't be misled by the small juveniles sold in stores.

What Do Turquoise Rainbowfish Eat?

They're not fussy eaters - feed a varied diet, rotating good-quality dry, frozen, and gel foods rather than the same thing every day, and match the food size to their mouths.

Turquoise Rainbowfish Tank Mates

Fast swimmer; best in 120cm+ tanks The Turquoise Rainbowfish is peaceful, which is the first thing to weigh up when you choose tank mates. It's a shoaling fish, so settle a group of 6 or more of its own kind before adding anything else - a stressed, lonely fish is far more likely to nip or hide. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.

Are Turquoise Rainbowfish Good for Beginners?

Often recommended to beginners, but only after the tank is cycled and you can keep a proper school - not three fish in a new setup.

Turquoise Rainbowfish - frequently asked questions

What size tank do Turquoise Rainbowfish need?

Turquoise Rainbowfish need a tank of at least 180 litres (48 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.

How many Turquoise Rainbowfish should I keep together?

Keep a group of at least 6. Turquoise Rainbowfish are a shoaling species and become stressed, lose their colour, or hide when kept singly or in pairs.

What water parameters do Turquoise Rainbowfish need?

Keep them at 75-82°F with a pH of 6.5-8, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.

What do Turquoise Rainbowfish eat?

Turquoise Rainbowfish are omnivores and aren't fussy eaters. Feed a varied mix of good-quality dry, frozen, and gel foods, and match the food size to their mouths. Feed small amounts once or twice a day, and remove anything they don't eat.

Are Turquoise Rainbowfish good for beginners?

Yes - Turquoise Rainbowfish are a good beginner choice once the tank is fully cycled and you can keep a proper group. They are hardy but still need stable water and a school to feel secure.

Common mistakes with Turquoise Rainbowfish

Buying fewer than 6 - Turquoise Rainbowfishs need a proper school to feel secure; isolated individuals hide, fail to colour up, or become stressed.
Underestimating tank size - the minimum footprint is 180 litres (48 US gallons); impulse buying into a smaller tank leads to stress and shortened lifespan.

Building a community? Run the full list through the stocking calculator before you add anything else.