The family Cyprinidae, carps and minnows, contains about eight percent of the world’s fish. The largest of the freshwater fish families, and the second largest vertebrate family (with Gobiidae – the gobies – the largest), Cyprinidae has over 2400 species in 220 genera (Nelson, 2006). Cyprinids are native to North America, Eurasia and Africa; fossil evidence suggests that this family may have originated in Asia in the Eocene. There are several characteristics of cyprinid fish:

• Their jaws are toothless; they chew their food using one or two rows of pharyngeal teeth and with gill rakers.

• They usually have large scales, but these are almost always absent from their head. They often have barbels around their mouth, and have no adipose fin. Cyprinids range in size from the 12 mm Danionella tanslucida to the 2.5 M long Catlocarpio siamensis

• Cyprinids are egg-layers that mostly spawn their eggs with no parental care.

• As members of the superorder Ostareophysi, cyprinids have a Weberian organ. This is a set of boney ossicles that connect the inner ear to the swim bladder, thus amplifying sound waves and allowing fishes to perceive a far greater range of auditory stimuli. This apparatus is thought to be important in the enormous diversification of otophysan fishes.

Many cypridid species are important food fish for humans, some have been farmed and fished for centuries. Popular sport fish, cyprinids are frequently stocked in ponds. Some are used as biocontrol agents to remove pests such as mosquitos, many are popular in the aquarium trade and as ornamental pets, and Danio rerio is an important organism bred in laboratories to study genetics and development. Cyprinids have been introduced world-wide and some cyprinids have become highly invasive. Cyprinus carpio, the common carp, is on the Invasive Species Specialist Group (ISSG)’s list of the world’s 100 worst invasive alien species.

(Rainer and Pauly 2010; ISSG; Nelson 2006; Wikipedia 2012)