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Aquarium fish are danger to rivers - 18th May 2026

Indonesia has a big problem with a fish. Its name is sapu-sapu. This tropical fish comes from South America. Now, Indonesia's rivers are full of them.

You often see sapu-sapu in home aquariums. They clean the glass with their mouths. People all over the world bought sapu-sapu for their aquariums.

Some sapu-sapu grew too big for their aquarium. In Indonesia, people put them in the river.

Sapu-sapu can grow up to 50 centimetres. The females lay thousands of eggs each year. They took over the rivers and ate all the food. Local fish didn't get enough to eat.

Sapu-sapu can live in dirty water. They don't need a lot of oxygen. Lots of Indonesia's rivers are polluted.

Now, there are too many sapu-sapu in the rivers. The problem's very bad in Jakarta. Local people are trying to stop these fish.

In two weeks, they caught 5.3 tonnes of sapu-sapu. They catch the sapu-sapu in nets.

People can't eat these fish. They have to kill them and bury them. They're full of pollution.

Muhammad Anwar: "It contains heavy metals and is dangerous to humans."

Animals from one region often cause problems in other places. They damage the local environment. Around the world, this costs $400 billion every year.