Thursday, June 3, 2010

Airsac catfish (Heteropneustes microps)

The airsac catfish is one of the more unusual fishes found in Sri Lanka – especially because it breathes air! While most fish have gills that help them take oxygen from their watery environment – this catfish has a long air sac that acts like a lung, allowing the catfish to breathe air.

Although they only grow to about 15cm long (about the same size as an adult’s hand) airsac catfish are dreaded by local fisherman due to the sharp poisonous spine in each pectoral fin that can give a painful sting on any person wading in its territory.

The fish hang out in schools of about ten. They are native to Sri Lanka and can be found in the south-west of the country. They mostly live in fresh and brackish water in areas affected by humans, such as ditches and swamps. At night you can find the fish looking for food and eating both plants and animals.

The fish are vulnerable to extinction – mainly because of chemicals used in farming that are washed into streams and rivers. Because these catfish live in small areas they are at an especially high risk of being affected by pollution.

To help protect these special fish, ask your family and friends to buy at least one item of organic food a week. Food which is produced organically is free of chemicals and don’t harm the animals that live in the area they are grown.

Four words you might not know…

Brackish: slightly salty water
Omnivore: an organism that feeds on both plants and animals.
School: a large group of fish
Pectoral fin: in fish, a pectoral fin is found on each side of the body just behind the gills. They are generally used for balancing and braking.

» Find out how else you can help to protect Sri Lanka's endangered species

Illustration by Asia Hewapathirana

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