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seven species: see text.
The archerfish (spinner fish or archer fish) are a family (Toxotidae) of fish known for their habit of preying on land-based insects and other small animals by shooting them down with water droplets from their specialized mouths. The family is small, consisting of seven species in the genus Toxotes; which typically inhabit brackish waters of estuaries and mangroves, but can also be found in the open ocean, as well as far upstream in fresh water. They can be found from India to the Philippines, Australia, and Polynesia.
Archerfish or spinnerfish bodies are deep and laterally compressed, 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 generally small,about 5–10 cm, but T. chatareus can reach 40 cm (16 in).
Archerfish are popular for aquaria.
Capture of prey
Archerfish are remarkably accurate in their shooting; adult fish almost always hit the target on the first shot. They can bring down insects and other prey on perches, up to 3 m above the water's surface. This is partially due to their good eyesight, but also their ability to compensate for the refraction of light as it passes through the air-water interface when aiming for their prey. 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°.
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, and its lips just break the surface, squirting a jet of water at its victim. It does this using the narrow groove in the roof of its mouth. It presses its tongue against this groove to form a narrow channel, then contracts its gill covers to force a powerful jet of water through the channel. The resulting jet of water can be up to 5 m long, but their accuracy allows them to shoot insects only 1–2 m away depending on body size. The fish can alter the power of the shot for prey of different sizes. If the first shot does not knock the victim into the water, the archerfish will keep trying.
Young archerfish start shooting when they are about 2.5 cm long, but are inaccurate at first and must learn from experience. During this learning period, they hunt in small schools. This way, the probability is enhanced that at least one jet will hit its target.
Archerfish will often leap out of the water and grab an insect in their mouths if it happens to be within reach. Individuals typically prefer to remain close to the surface of the water.
- Toxotes blythii (Boulenger, 1892) - clouded archerfish, zebra archerfish
- Toxotes chatareus (Hamilton, 1822) - largescale archerfish
- Toxotes jaculatrix (Pallas, 1767) - banded archerfish
- Toxotes kimberleyensis (Allen, 2004) - Kimberley archerfish
- Toxotes lorentzi (Weber, 1910) - primitive archerfish
- Toxotes microlepis (Günther, 1860) - smallscale archerfish
- Toxotes oligolepis (Bleeker, 1876) - big scale archerfish, western archerfish
- Two submarines of the United States Navy have been named USS Archerfish, the first one holding the distinction of sinking the largest ship ever destroyed by a submarine, the 68,059-ton Japanese aircraft carrier Shinano, on November 29, 1944.
- Projectile use by living systems
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- ""Plastic flies help spitting archer fish regain aim" Telegraph.co.uk". The Telegraph. 2002-07-11. Retrieved 2009-05-24.
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- Temple, S. E. "Effect of salinity on the refracive index of water: considerations for archer fish aerial vision" 'Journal of Fish Biology' Vol 70, 1626–1629 2007.
- Temple, S.E., Hart, N. S., and Colin, S. P. "A spitting image: visual specializations of the arsherfish (Toxotes chatareus)" 'Brain Behaviour and Evolution' Vol. 73, 309 2009.
- Froese, Rainer, and Daniel Pauly, eds. (2006). "Toxotidae" in FishBase. January 2006 version.
- Froese, Rainer, and Daniel Pauly, eds. (2006). Species of Toxotes in FishBase. January 2006 version.