Food Cyprinids are highly important food fish; they are
fished and
farmed across
Eurasia. In
land-locked countries in particular, cyprinids are often the major species of fish eaten because they make the largest part of
biomass in most water types except for fast-flowing rivers. In Eastern Europe, they are often prepared with traditional methods, such as drying and salting. The prevalence of inexpensive
frozen fish products made this less important now than it was in earlier times. Nonetheless, in certain places, they remain popular for food, as well as
recreational fishing, for ornamental use, and have been deliberately stocked in ponds and lakes for centuries for this reason.
Sport Cyprinids are popular for angling especially for
match fishing (due to their dominance in biomass and numbers) and fishing for common carp because of its size and strength.
As pest control Several cyprinids have been introduced to waters outside their natural ranges to provide food, sport, or biological control for some
pest species. The common carp (
Cyprinus carpio) and the grass carp (
Ctenopharyngodon idella) are the most important of these, for example in
Florida.
As a pest species Carp in particular can stir up
sediment, reducing the clarity of the water and making plant growth difficult. In America and Australia, such as the
Asian carp in the
Mississippi Basin, they have become
invasive species that compete with native fishes or disrupt the environment.
Cyprinus carpio is a major pest species in
Australia impacting freshwater environments, amenity, and the agricultural economy, devastating
biodiversity by decimating native fish populations where they first became established as a major pest in the wild in the 1960s. In the major river system of eastern Australia, the
Murray-Darling Basin, they constitute 80–90 per cent of fish biomass. In 2016 the federal government announced A$15.2 million to fund the National Carp Control Plan to investigate using
Cyprinid herpesvirus 3 (carp virus) as a biological control agent while minimising impacts on industry and environment should a carp virus release go ahead. Despite initial, favourable assessment, in 2020 this plan was found to be unlikely to work due to the high fecundity of the fish.
Aquarium fish Numerous cyprinids have become popular and important within the
aquarium and fishpond hobbies, most famously the
goldfish, which was bred in China from wild Carassius species (
Carassius auratus). First imported into Europe around 1728, it was originally much-fancied by the Chinese nobility as early as 1150AD and, after it arrived there in 1502, also in
Japan. In addition to the goldfish, the amur carp was bred in Japan into the colorful ornamental variety known as
koi — or more accurately , as simply means "common carp" in
Japanese — from the 18th century until today. Other popular aquarium cyprinids include
danionins,
rasborines and
true barbs. Larger species are bred by the thousands in outdoor ponds, particularly in
Southeast Asia, and trade in these aquarium fishes is of considerable commercial importance. The small rasborines and danionins are perhaps only rivalled by
characids (tetras) and
poecilid livebearers in their popularity for
community aquaria. Some of the most popular cyprinids among
aquarists, other than goldfish and koi, include the
cherry barb,
Harlequin rasbora,
pearl danios,
rainbow sharks,
tiger barbs, and the
White Cloud Mountain minnow. One particular species of these small and undemanding danionins is the
zebrafish (
Danio rerio). It has become the standard
model species for studying developmental genetics of
vertebrates, in particular fish.
Conservation Habitat destruction and other causes have reduced the wild stocks of several cyprinids to dangerously low levels; some are already entirely
extinct. In particular, the cyprinids of the subfamily
Leuciscinae from southwestern North America have been severely affected by
pollution and unsustainable water use in the early to mid-20th century. The majority of globally extinct
cypriniform species in fact belong to the leuciscinid cyprinids from the southwestern United States and northern Mexico. ==Systematics==