The archerfish are noted for obtaining insects by shooting them down with a stream of water drops. Learn all about it!
The archerfish and any of the other five species are noted for obtaining insects by shooting them down with a stream of water drops. These fish can reach up to one foot in length and makes its home in the brackish waters of mangrove belts, in the ocean and they have even been know to go up stream to fresh water. The first accurate account of the archerfish shooting down its prey was written in 1765 by the Dutch governor of a hospital in Batavia, now Jakarta, which is the capital of Java. The governor made the decision to send a specimen to Europe with a description of amazing feat performed by the archerfish. By mistake the specimen the governor sent was a butterfly fish and scientist discounted the report saying it was impossible. Finally in 1902 a Russian scientist obtained some specimens and kept them in an aquarium to verify the shooting abilities of the archerfish.
The main food of the archerfish consists of small water animals swimming or floating near the surface, but if they are hungry, they shoot down insects crawling on leaves and stems in over hanging vegetation. An adult that is fully grown can hit insects that are six feet above the water. One archerfish was observed shooting a jet of water that traveled 15 feet when it missed its target. When this fish misses with its first stream it will shoot several more in rapid succession. When it is shooting down prey the tip of the snout breaks the waters surface with the eyes still submerged. Water in the gill chamber is driven into the mouth by its powerful compression of the gill covers and the tongue presses upward converting a groove in the roof of the mouth into a tube. This increases the out going stream of water.
Adult archerfish spawn far from land in regions of coral rock or coral reef. After the young are hatched they return to the brackish water or beyond to fresh water. The archerfish begin to spit when very young and only a few centimeters long but the jets of water they produce do not travel much over 4 inches. As they grow their marksmanship improves and the length they spit increases. The young have dark bars on the back with light flecks on the back between the bars. From time to time the specks shine so bright that they appear to be tiny greenish fluorescent lights. This is believed to be recognition marks between the species that help them keep together in muddy waters. Archerfish can be found from India through south east Asia, the Malay Archipelago and parts of Australia to the Philippines.
Scientist have tried to understand how the archerfish can hit its target with its eyes beneath the water. It was assumed that the fish in some way allows for the refraction. But in 1961 a more careful observation of the archerfish feeding on insects showed that the fish swims forward until it is almost under its target, appears to take aim, then ejects the water jet while jerking its body nearly vertical. In this position, just as with a stick that is dipped straight into water does not appear bent since refraction is reduced to a minimum, the archerfish is looking straight up out of the water and sees the exact position of its prey. Even so, it is believed that the archerfish must be some what intelligent since their marksmanship improves with practice which indicates a learning ability.