Pacu

The common name pacu is generally applied to fish classified under the below listed genera. • Subfamily Colossomatinae • Colossoma – black pacu, black-finned pacu, giant pacu • Mylossoma • Piaractus – red-bellied pacu, small-scaled pacu • Subfamily Myleinae • Mylesinus • Myleus • Myloplus • Ossubtus – parrot pacu, eaglebeak pacu • Paramyloplus • Prosomyleus • Tometes • Utiaritichthys • Subfamily Serrasalminae • Metynnis Each of these groups contains one or more separate species. For example, the fish often found in pet stores, known as the black pacu and red-bellied pacu, typically belong to the species Colossoma macropomum and Piaractus brachypomus, respectively. A species popular among fish farmers is Piaractus mesopotamicus, also known as Paraná River pacu or small-scaled pacu. Pacu is a term of Tupi-Guaraní origin. When the large fish of the genus Colossoma entered the aquarium trade in the U.S. and other countries, they were labeled pacu. In the Brazilian Amazon, the term pacu is generally reserved to smaller and medium-sized fish in the Metynnis, Mylossoma, Mylesinus and Myleus genera. Colossoma macropomum are known as tambaqui, whereas Piaractus brachypomus is known as pirapitinga. In Peru, both of the species (Colossoma macropomum and Piaractus brachypomum) are called pacú and gamitana. Piaractus mesopotamicus of the Paraná-Paraguay basin is also called pacú in Paraguay and Argentina. == Classification ==

Pacu, along with their piranha relatives, are a characin fish, meaning a kind of tetra, belonging to the Characiformes order. The ongoing classification of these fish is difficult and often contentious, with ichthyologists basing ranks according to characteristics that may overlap irregularly. DNA research sometimes confounds rather than clarifies species ranking. Ultimately, classifications can be rather arbitrary. Pacu, along with piranha, are currently further classified into the family Serrasalmidae (formerly a subfamily of Characidae). Serrasalmidae means "serrated salmon family" and refers to the serrated keel running along the belly of these fish. However, dental characteristics and feeding habits further separate the two groups from each other. ==Native distribution and habitat==

Pacus are native to tropical and subtropical South America. They inhabit rivers, lakes, floodplains and flooded forests in the Amazon, Orinoco, São Francisco River and Río de la Plata Basins, as well as rivers in the Guianas. Here they form part of the highly diverse Neotropical fish fauna. Their habitat preferences varies significantly depending on the exact species. Several species are migratory. ==As exotic species==

Pacus have been introduced to the wild in many places outside their native range, both in South America and other continents. They are sometimes released to increase the local fishing, but others are released by aquarists when they outgrow their aquarium. This is illegal in many countries and strongly advised against. United States Pacus have become established in Puerto Rico and singles have been caught in numerous U.S. states. Discoveries have been reported in Alabama, Arkansas, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Kansas, Massachusetts, Michigan, Minnesota, Mississippi, Nebraska, New Hampshire, New Jersey, North Dakota, Ohio, Oklahoma, Texas, Utah, Washington, Wisconsin, and Wyoming. Additionally, aquarium-raised fish can be eaten (see Food fish). An angler fishing on the river Seine in Paris, France, caught a pacu in August 2013. In June 2016, a pacu was caught in a city pond in Tula, Russia. In June 2017, a pacu was accidentally caught during a fishing contest at the Port of Drobeta Turnu Severin, Romania. The fish bit one of the fishermen, leading to a general warning being issued in the region, until the origin of the fish can be determined. In August 2017, a pacu was caught in the stream Motala Ström in Norrköping, Sweden. In July 2019, two pacus were caught near Baia Mare, Romania. In September 2020, a pacu weighing approx. was caught in Zegrze Reservoir in Poland. In February 2024, a dead pacu was found in Garadice Lough, Ireland. In Summer 2025 a pacu got fished out of the Jagst River near Crailsheim in southern Germany. Asia Pacus have become established in tropical Asia, including Vietnam, Malaysia, Bangladesh, Thailand, and India. New Guinea Pacu were introduced in 1994 to the Sepik River, and in 1997 to the Ramu river as a food source, due to overfishing of native species. Local people blame the fish for outcompeting native species, including juvenile crocodiles, as well as for several attacks on humans. As a primarily vegetarian fish, red-bellied pacu, have also consumed the floating mats of vegetation in the Sepik River, which operated as fish nurseries and crocodile and bird nesting sites. Thus the entire ecosystem has become impoverished and local people cannot subsist as easily as they once did. ==Importance to humans==

In their native range, pacus are widely fished and farmed. Based on a study by IBAMA, Colossoma macropomum, Piaractus brachypomus and Mylossoma spp. are all in the top-15 of the most caught fish (by weight) in the Brazilian Amazon. (see also online version), Theodore Roosevelt advised, "For small fish like the pacu and piranha an ordinary bass hook will do." Concerning the pacu, he added: "A light rod and reel would be a convenience in catching the pacu. We used to fish for the latter variety in the quiet pools while allowing the canoe to drift, and always saved some of the fish as bait for the big fellows. We fished for the pacu as the native does, kneading a ball of mandioc farina with water and placing it on the hook as bait. I should not be surprised, though, if it were possible, with carefully chosen flies, to catch some of the fish that every once in a while we saw rise to the surface and drag some luckless insect under." More recently, South American rivers including the Amazon have become a popular destination for recreational anglers, who go to fly fish for pacu. The International Game Fish Association has sponsored fly-fishing courses for native Brazilian fishermen, typically accustomed to subsistence fishing, so they can work as guides to fishing tourists. s, with a lemon-half garnish.Photograph taken in Villa Tunari, Bolivia, by Marc Alan Davis. Food fish Theodore Roosevelt wrote of catching and eating pacu in his book Through the Brazilian Wilderness. Aquaculture may relieve the overfishing crisis, as well as improve food security by boosting fish supplies. Various species of pacu are increasingly being used for warm-water farm fishing around the world. Pacu are considered ideal for their tolerance of the low-oxygen water in farm ponds. They also don't require a lot of expensive protein in their diet, and can be raised year-round in warm or temperature-controlled environments. Research shows that the "flavor of [farmed] pacu is comparable to that of hybrid striped bass, tilapia, and rainbow trout, but superior to catfish."{{cite journal Aquarium-raised pacu can be cooked and eaten, but care should be taken to ensure that no toxic medications were used in the aquarium. A recipe and preparation instructions are provided on the Greater Seattle Aquarium Society's Web site. ==Incorrect claim of testicle-biting==

In 2013, a pacu was caught in the Øresund Sound, a strait between Sweden and Denmark. This led to media reports mistakenly warning that the fish could attack testicles. The reports were based on a joke (referring to their actual feeding on tree nuts) that was not meant to be taken seriously. Nevertheless, their very strong jaws made for crushing plant seeds and the like means that fishermen and aquarists sometimes are warned about the powerful bite that may cause traumatic injuries. == References ==