Archer fish have a unique method of hunting their prey – they shoot a powerful jet of water at prey perched on leaves or rocks close to the surface of the water. The prey becomes a quick lunch when in drops into the water.
Recently scientists have been able to study this behaviour in more detail, using a high-speed camera. This data from the camera can be used to monitor the force and velocity of the jet as the archer fish shoots water at its prey.
The study found that the archer fish continously change the shape of their mouth when shooting the water jet, allowing them to aim at prey perched at different heights and distances.
When aiming at targets that were further away, the archer fish opened its mouth more slowly, so the jet of water remained stable for longer time periods. When aiming at targets close by, the fish forced the water out at a much faster rate. In both cases, the water at the end of the stream was shot out at a faster rate than the beginning, giving the prey very little time to react.