Harlequin rasboras are one of the best beginner shoaling fish — hardy, peaceful, and instantly recognisable by the bold black triangle on their copper-orange bodies. They shoal tightly, tolerate a wide range of water, and suit almost any peaceful community tank, making them a reliable alternative to more fragile tetras.
Here is how to keep them.
- Harlequin rasboras are hardy, peaceful shoaling fish ideal for beginners.
- Keep a shoal of at least eight in a planted 60-litre-plus tank.
- They are adaptable to most UK water but colour up best over dark substrate.
- They mix well with tetras, corydoras, gouramis and shrimp.
Quick facts
- Adult size: 4–5 cm
- Tank size: 60 litres for a shoal of 8+
- Water: pH 6.0–7.5, soft to medium, 22–27 °C
- Lifespan: 5–6 years
- Temperament: peaceful, shoaling
Tank setup
Harlequins look their best in a planted tank with dark substrate and gentle flow, where their orange colour glows. They are adaptable to most UK water but prefer slightly soft, neutral conditions. Keep the tank cycled and stable — see how to cycle a tank.
Shoaling and feeding
Keep at least eight; they are a true shoaling fish and feel insecure in smaller numbers. Feed a varied diet of quality flake, micro pellets and frozen foods.
Tank mates
Excellent with tetras, ember tetras, honey gouramis, corydoras, cherry shrimp and other peaceful community fish. Avoid fin-nippers and large predators.
Frequently asked questions
How many harlequin rasboras should be kept together?
At least eight. They are shoaling fish that feel secure and show their best colour and behaviour in groups.
Are harlequin rasboras good for beginners?
Yes — they are among the hardiest and most adaptable small shoaling fish, tolerating a wide range of water conditions in a peaceful community tank.
What do harlequin rasboras eat?
A varied omnivore diet of quality flake, micro pellets and frozen foods such as daphnia and brine shrimp. Their small mouths suit small foods.
— Jaqline Smalling, FishForever
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