Peacock bass

Peacock bass (Cichla) is a genus of large cichlids, diurnal and predatory freshwater fish native to the Amazon and Orinoco basins, as well as rivers of the Guianas, in tropical South America. They are sometimes referred to in English by their Brazilian name tucunaré or their Spanish name pavon. Despite the common name and their superficial similarity, they are not closely related to other fish known as bass, such as the North American largemouth bass (Micropterus salmoides). Peacock bass are important food fish and also considered game fish. This has resulted in their accidental (escapees from fish farms) or deliberate (release by fishers) introduction to regions outside their native range, both elsewhere in South America, and in warm parts of North America and Asia. Singles have been caught elsewhere, including Australia, but do not appear to have become established there. Where established as an introduced species, they may become invasive and damage the ecosystem because of their highly predatory behavior, feeding extensively on smaller native fish. The largest species in the genus, the speckled peacock bass (C. temensis), reaches up to 13 kg (29 lb) in weight and 1 m (3.3 ft) in length, possibly making it the largest species of cichlid (others suggest that prize goes to the African giant cichlid, Boulengerochromis microlepis). Other peacock bass species are smaller. They are sometimes kept in aquariums, but even the smaller species require a very large tank. Following a taxonomic review published in 2006, 15 Cichla species are recognized by FishBase: In addition, possibly undescribed species of peacock bass are known from the Travessão and Paru Rivers in Brazil. Traditionally, only five peacock bass were recognized, but in the review in 2006, nine new species were described and C. nigromaculata was revalidated. In general, the various species are similar in proportions and most meristics, but differ in colour pattern (and range). This is similar to other diurnal cichlids, where visual clues play an important role in the behavior, including breeding. The speckled or three-barred peacock bass (C. temensis) in particular has caused problems due to its extensive variation, but the speckled pattern has now been shown to be present in nonbreeders and the three-barred when breeding. Although minor variations are known from adults of other peacock bass species, none shows the extreme variation of the speckled/three-barred peacock bass. A genetic study published in 2012 has cast doubt on the validity of some of the species recognized in the review in 2006. Aside from limited hybridization among many species, in both natural and human-altered environments, several species do not show sufficient differentiation to imply reproductive isolation and/or a history of independent evolution. Among the species implicated as probable 'good' species were C. intermedia, C. orinocensis, C. temensis, C. melaniae, C. mirianae, and C. piquiti. The other species were suggested to be part of two widespread meta-species or species complexes, called Cichla pinima sensu lato (including C. jariina, C. thyrorus, and C. vazzoleri) and C. ocellaris sensu lato (including C. monoculus, C. nigromaculata, C. pleiozona, and C. kelberi). In contrast, a genetic study published in 2007 suggested that two of those demoted taxa, C. monoculus and C. pleiozona, are valid species (this study lacked samples from some of the more localized proposed species). The peacock bass genus Cichla has been placed by some authorities as the only genus in the monogeneric tribe Cichlini.