Interesting Creature… Peacock bass

Sep 11, 2022 Interesting Creatures in Guyana, News

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Kaieteur News – Peacock bass or Brazilian tucunaré are large freshwater cichlids of the genus Cichla. These are diurnal predatory fishes, 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 valuable 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 behaviour, 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.

In addition, possibly undescribed species of peacock bass are known from the Travessão and Paru Rivers in Brazil.

Traditionally, only five peacock bass were recognised, 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 behaviour, 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 non-breeders 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 recognised 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.

Common names

Many common names are used for these fish in Brazil, the country of their largest native region. The most popular of these is tucunaré. In Spanish, the generic common name for these cichlids is pavόn. Pavón, in Spanish, means “peacock”, while the Brazilian name comes from Tupi, an indigenous language of Brazil, meaning “friend of the tree”, as this peacock bass usually stays close to submerged trees to hunt and to protect itself and its nests.

Description

The speckled peacock bass is the largest species and can grow to 1 m (3.3 ft) in length, and may be the largest of all cichlid fishes. Most display a colour pattern based on a theme of three wide vertical stripes on their bodies, sometimes with smaller intermediate bands, only a grey, brown, yellow, or green background. They also exhibit a spot on their tail fins that resembles the eyes on a peacock’s tail feathers—a feature which resulted in their common names (this “ocellus” is a common feature of South American cichlids, and is thought to deter predators and fin-biting piranhas). In addition, many adult fishes (primarily males, but also some females) develop a pronounced hump on their foreheads (nuchal hump) shortly before and during the rainy season, when the fishes generally spawn. Other physical traits can vary greatly, depending on the species, individual, and stage of development. These include dark rosettes instead of stripes, light speckles, and impressive shades of bright green, orange, blue, and gold. Very young fish exhibit dark horizontal stripes down half body.

Conservation status

The IUCN has not investigated the conservation status of any peacock bass species. Therefore, they do not appear on its red list. Some of the species have relatively small distributions, and C. melaniae is restricted to the lower Xingu River in the state of Pará, Brazil, in an area heavily affected by the Belo Monte Hydroelectric Dam. (Source: Wikipedia)

 

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