What do archerfish shoot to knock insects off branches?

Archerfish shoot jets of water to knock insects off branches and other vegetation above the water. The fish aims upward, presses its tongue against the roof of its mouth to form a narrow channel, and rapidly closes its gill covers. This pressure sends a focused stream toward the target.

The technique is remarkably precise because the fish must account for the way light bends at the water's surface. An archerfish can bring down prey as high as about 3 meters above the water. The falling insect then becomes accessible to the fish, which usually snaps it up from the surface.

Archerfish belong to the family Toxotidae, containing roughly ten species in the genera Toxotes and Protoxotes. They live from India and Sri Lanka through Southeast Asia to northern Australia and Melanesia. Most inhabit fresh water, though some tolerate brackish estuaries and mangroves.

Young fish begin shooting when they are only about 2.5 centimeters long and improve with experience. Researchers have also found that archerfish can learn by watching other individuals, making this one of the most striking examples of specialized predation in fish.