FASCINATING FACT

Fish Facts: Part One

The world’s smallest fish is the tiny cyprinid fish Paedocypris progenetica from forest swamps in Indonesia. Mature females measure only 7.9mm. The fish has a translucent body and the head is unprotected by any bony skeleton.

Fish have an inbuilt sonar system which allows them to navigate in dark or in cloudy waters. The fish can pick up pressure waves using cells in the lateral line that runs along the side of the body from the head to the tail. This allows them to locate prey that is moving. While swimming the fish also produce pressure waves which bounce off underwater objects and are picked up by the lateral line – giving the fish a sonar picture of its surroundings.

The scales of a fish can tell you a lot about its history. The scales are formed in rings, which are closer together if the fish is growing slowly, and wider apart if the fish is growing quickly. For example, if the fish is in a seasonal environment such as a lake or river in the UK, several rings will be close together during the winter and, by counting the bands of closely spaced rings, you can tell the age of the fish.