Clown loaches are among the most charming and social fish in the hobby — orange-and-black striped, endlessly playful, and famous for eating pest snails. But they carry a warning almost every shop forgets to mention: they reach 30 cm, live for decades, and must be kept in groups, so they need a much bigger tank than their cute juvenile size suggests.

Here is what you’re really signing up for.

Quick facts

• Adult size: up to 30 cm (yes, really)
• Tank size: 450 litres minimum for a group
• Water: pH 6.0–7.5, soft to medium, 25–30 °C
• Lifespan: 15–20+ years
• Temperament: peaceful, highly social

The size and group truth

Shops sell clown loaches at 4–5 cm, but they grow slowly to 25–30 cm and can live over 20 years. They are also intensely social and must be kept in groups of five or more — lone clown loaches become stressed and hide. A proper group needs a 450-litre-plus tank. Do not buy them for a small aquarium.

Behaviour and feeding

Clown loaches are bottom-dwellers that love caves and will happily lie on their sides “playing dead” — a normal, if alarming, habit. They eat pest snails, sinking wafers, frozen foods and vegetables. Provide plenty of hiding caves.

They can be prone to ich, so quarantine new arrivals — see quarantine setup.

Tank mates

Peaceful larger community fish suit them: angelfish, gouramis, larger tetras, plecos and rainbowfish. Avoid tiny fish they might intimidate and aggressive cichlids.

Frequently asked questions

How big do clown loaches get?

Up to 30 cm in a large aquarium, though they grow slowly. Their eventual size is why they need a very large tank despite being sold small.

Can you keep a single clown loach?

No — they are intensely social and become stressed and reclusive alone. Keep a group of at least five.

Why is my clown loach lying on its side?

This is normal behaviour — clown loaches often rest or 'play dead' on their sides. As long as it is otherwise active and feeding, there is no cause for concern.

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— Jaqline Smalling, FishForever