Bighead Carp

The bighead carp (Hypophthalmichthys nobilis) is a large filter-feeding fish native to major rivers of eastern China, closely related to the silver carp but distinguished by its disproportionately large head and dark, irregular mottled blotches across its silvery-olive flanks. Native to the Yangtze, Pearl, and other Chinese river systems, bighead carp were widely introduced for aquaculture and algae control and have since become established as an invasive species in parts of the Mississippi River basin in the United States, where they compete with native plankton-feeding fish. They can grow to substantial size, sometimes exceeding 40 kilograms, and primarily feed on zooplankton, complementing the more phytoplankton-focused diet of the related silver carp.

• Very large, broad head relative to body size, giving the species its name
• Dark grey to black irregular mottled blotches scattered over a silvery-olive body
• Eyes positioned low on the head, below the midline
• Wide, upturned, toothless mouth without a keeled belly (unlike silver carp)
• Look-alikes: silver carp is more uniformly silvery without dark blotches and has a keeled belly running further forward; both species are often confused but bighead is generally larger-headed and darker-patterned

Bighead carp are native to large, slow-to-moderate flowing rivers and their floodplain lakes in eastern China, particularly the Yangtze and Pearl river systems, and have been introduced across much of the world for aquaculture. They favor open water in rivers, reservoirs, and large lakes with abundant zooplankton, typically inhabiting the middle to upper water column rather than the bottom. In North America, bighead carp have become established in the Mississippi, Missouri, and Illinois river systems, where they thrive in warm, nutrient-rich water and are considered a significant threat to native aquatic ecosystems due to competition for plankton resources shared with native fish and mussel larvae.

Bighead carp are filter feeders specialized for straining zooplankton, along with some phytoplankton, from the water using fine gill rakers, enabling rapid growth to large sizes without preying on other fish. Unlike silver carp, bighead carp are less prone to leaping from the water when startled, though they can still be disturbed by boat activity. Spawning occurs in warm months in flowing river reaches, where females release vast numbers of semi-buoyant eggs that drift with the current during development; there is no parental care of eggs or young. Bighead carp can live for over twenty years and reach very large sizes, and their prolific reproduction combined with efficient filter feeding has allowed populations to expand aggressively in introduced ranges, prompting active management and control efforts.