Fishes are the most numerous organisms among the vertebrates and they number more than 30, 000, which is more than all the other back boned animals put together. Each group has its own way of acquiring food. The archer fish spits pellets of water to shoots down insects sitting on overhanging plants. Its aim is quite accurate and it can easily dislodge a fly or beetle about four feet away so that it falls into the water. The archer-fish then dashes towards the insect and eats it.
Archer Fish Spits Insects
It is interesting to know how this fish is able to direct the jet of water exactly at the intended target over four feet away. The roof of its mouth forms a long groove. If the fish suddenly closes its gill covers, water is forced from the gill chamber into the mouth. At the same time, the tongue is raised, so the groove becomes a long tube from which the water squirts in a jet. Even more remarkable, it has adapted to the refractive index-caused perspective distortion air and water have different indices of refraction; this means that an insect is not where it appears to be, when see form underwater! If you have seen a spoon bending in glass tumbler of water, you know why it is such a feat for the archerfish to shoot insects down form underwater, you to shoot insects down from underwater. They improve their chances of a kill by swimming as directly under the prey as possible, so that the distortion is at a minimum.
The archerfish is a fresh water fish, and belongs to the family toxobidae. It is found in India and Indonesia
