Elephant Puppet Meets The Archerfish
4The archerfish (also known as spinner fish or archer fish) or Toxotidae are a monotypic family of perciform tropical fish known for their unique predation technique of "shooting down" land-based insects and other small prey with jets of water spit from their specialized mouths. The family is small, consisting of ten species in a single genus, Toxotes. Most archerfish live in freshwater streams, ponds and wetlands, but two or three species are euryhaline, inhabiting both fresh and brackish water habitats such as estuaries and mangroves.[1][2] They can be found from India, Bangladesh and Sri Lanka, through Southeast Asia, to Melanesia and Northern Australia.[3]
Archerfish have deep and laterally compressed bodies, with the dorsal fin and the profile a straight line from dorsal fin to mouth. The mouth is protractile, and the lower jaw juts out. Sizes are fairly small, typically up to about 12–18 cm (5–7 in), but T. chatareus can reach 40 cm (16 in).[3][4]
Archerfish are popular exotic fish for aquaria,[5] but are difficult to feed and maintain by average fishkeepers since they prefer live prey over typical fish foods.
Archerfish are remarkably accurate in their shooting; an adult fish almost always hits the target on the first shot. Although it is presumed that all archerfish species do this, it has only been confirmed from T. blythii, T. chatareus and T. jaculatrix.[1] They can bring down insects and other prey[6] up to 3 m (10 ft) above the water's surface.[7] This is partially due to their good eyesight, but also to their ability to compensate for the refraction of light as it passes through the air-water interface when aiming at their prey.[8] They typically spit at prey at a mean angle of about 74° from the horizontal but can still aim accurately when spitting at angles between 45° and 110°.[9]
When an archerfish selects its prey, it rotates its eye so that the image of the prey falls on a particular portion of the eye in the ventral temporal periphery of the retina,[10] and its lips just break the surface, squirting a jet of water at its victim. The archerfish does this by forming a small groove in the roof of its mouth and its tongue into a narrow channel. It then fires by contracting its gill covers and forcing water through the channel, shooting a stream that, shaped by its mouth parts, travels faster at the rear than at the front. This speed differential causes the stream to become a blob directly before impact as the slower leading water is overtaken by the faster trailing water, and it is varied by the fish to account for differences in range. It also makes this one of the few animals that both make and use tools, as they both utilise the water and shape it to make it more useful to them.[11][12] They are persistent and will make multiple shots if the first one fails.[13]