Cyprinidae

The Cyprinidae are the family of freshwater fishes, collectively called cyprinids, that includes the carps, the true minnows, and their relatives (for example, the barbs and barbels). Also commonly called the 'carp family', or 'minnow family', Cyprinidae is the largest and most diverse fish family and the largest vertebrate animal family in general, with about 3,000 species of which only 1,270 remain extant, divided into about 370 genera.. They range from about 12 mm to the 3-m Catlocarpio siamensis. These fish are some of the few that do not take care of their eggs. The family belongs to the ostariophysian order Cypriniformes, of whose genera and species the cyprinids make up more than two-thirds. The family name is derived from the Ancient Greek kyprînos (κυπρῖνος, 'carp'). Cyprinids are stomachless fish with toothless jaws. Even so, food can be effectively chewed by the gill rakers of the specialized last gill bow. These pharyngeal teeth allow the fish to make chewing motions against a chewing plate formed by a bony process of the skull. The pharyngeal teeth are unique to each species and are used by scientists to identify species. Strong pharyngeal teeth allow fish such as the common carp and ide to eat hard baits such as snails and bivalves. Hearing is a well-developed sense in the cyprinids since they have the Weberian organ, three specialized vertebral processes that transfer motion of the gas bladder to the inner ear. The vertebral processes of the Weberian organ also permit a cyprinid to detect changes in motion of the gas bladder due to atmospheric conditions or depth changes. The cyprinids are considered physostomes because the pneumatic duct is retained in adult stages and the fish are able to gulp air to fill the gas bladder, or they can dispose of excess gas to the gut. Cyprinids are native to North America, Africa, and Eurasia. The largest known cyprinid is the giant barb (Catlocarpio siamensis), which may grow up to 3 m (9.8 ft) in length and 300 kg (660 lb) in weight. Other very large species that can surpass 2 m (6.6 ft) are the golden mahseer (Tor putitora) and mangar (Luciobarbus esocinus). The largest North American species is the Colorado pikeminnow (Ptychocheilus lucius), which can reach up to 1.8 m (5.9 ft) in length. Conversely, many species are smaller than 5 cm (2 in). The smallest known fish is Paedocypris progenetica, reaching 10.3 mm (0.41 in) at the longest. All fish in this family are egg-layers and most do not guard their eggs; however, a few species build nests and/or guard the eggs. The bitterlings of subfamily Acheilognathinae are notable for depositing their eggs in bivalve molluscs, where the young develop until able to fend for themselves. Most cyprinids feed mainly on invertebrates and vegetation, probably due to the lack of teeth and stomach; however, some species, like the asp, are predators that specialize in fish. Many species, such as the ide and the common rudd, prey on small fish when individuals become large enough. Even small species, such as the moderlieschen, are opportunistic predators that will eat larvae of the common frog in artificial circumstances. Some cyprinids, such as the grass carp, are specialized herbivores; others, such as the common nase, eat algae and biofilms, while others, such as the black carp, specialize in snails, and some, such as the silver carp, are specialized filter feeders. For this reason, cyprinids are often introduced as a management tool to control various factors in the aquatic environment, such as aquatic vegetation and diseases transmitted by snails. Unlike most fish species, cyprinids generally increase in abundance in eutrophic lakes. Here, they contribute towards positive feedback as they are efficient at eating the zooplankton that would otherwise graze on the algae, reducing its abundance.