The silver carp (Hypophthalmichthys molitrix), also called the flying carp, is a species of freshwater cyprinid fish, a variety of Asian carp native to north and northeast Asia. With its tendency to leap from the water when startled, this fish is cultivated in China. Capable of growing to over 40 lb (18 kg), this fish can often leap 10 feet or 3 meters in the air.

Silver carp is a filter feeder, and possesses a remarkably specialized filtration apparatus capable of filtering particles as small as 4 µm. Silver carps are produced worldwide in aquaculture. The gill rakers are fused into a sponge-like filter, and an epibranchial organ secretes mucus which assists in trapping small particles. A strong buccal pump forces water through this filter.

Like all Hypophthalmichthys species, this carp has no stomach, as they feed constantly. Silver carp are thought to feed largely on phytoplankton; they also consume zooplankton and detritus. Because of their plankton feeding habit, they have been successfully used as methods for controlling water quality, especially in the control of noxious cyanobacteria (blue-green algae).  For instance, millions silver carps have been released in the past in Taihu Lake, one of the nation’s most scenic lakes, that straddles Jiangsu and Zhejiang provinces, to feed on the blue-green algae plague due to the pollution from the sewage, agricultural and industrial waste. 

However, these efforts are sometimes not successful. Certain species of blue-green algae, notably the often toxic Mycrocystis, can pass through the gut of silver carp unharmed, and pick up nutrients while in the gut. Thus, in some cases blue-green algae blooms have been exacerbated by silver carp. Also, Mycrocystis has been shown to produce more toxins in the presence of silver carp. Silver carp, which have natural defenses to the toxins produced by blue-green algae, sometimes can contain enough algal toxins in their systems that they become hazardous to eat.

Silver carp are also considered as a highly invasive species, often reaching an extremely high population densities bringing undesirable effects on the environment and on native species. Considering the diet of blue-green algae this fish feeds on, one may think twice whether to feed on them as part of their diet.