Archerfish are small tropical fish that spit jets of water to knock insects as high as 10 feet above the surface so they can eat them. Their mouths are described by biologists as being like tiny guns, and their aim is highly accurate, their brains taking refraction through the water surface into account when targeting prey, and is considered an example of animals using tools. Juveniles hunt in groups to learn how to aim better, but adults almost never miss the first shot. They're also a popular, though challenging, aquarium pet.