Animal Vision: Eyes on two worlds

In the tidal waters of tropical mangrove swamps lurks an unassuming little fish. It is about 25cm long, silvery in colour with several black bands across its back. It is an omnivore, eating floating plant matter as well as crustaceans and other small fish. But there is far more to this fish than meets the eye, and the clue is in its name; the archerfish.

Archerfish have a rare talent, if ‘talent’ is the right word for having the ability to shoot a directed jet of water up to two metres into the air. They can use these jets to knock flying insects out of the air or off of their perches and onto the water surface, where they are quickly snapped up by the hungry archerfish. Their jets are also effective underwater, stunning small invertebrates long enough for them to be picked off by the archerfish as an easy meal. Water or air, nowhere it seems, is safe from a hungry archerfish.