Redeye piranha

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Redeye piranha

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Characiformes
Family:	Characidae
Genus:	Serrasalmus
Species:	S. rhombeus

Binomial name

Serrasalmus rhombeus
(Linnaeus, 1766)

The redeye piranha or black piranha, Serrasalmus rhombeus, is a fish of the piranha family Characidae found in South America in the Amazon and Orinoco river basins, the north and eastern Guiana Shield rivers, and northeastern Brazilian coastal rivers. Its length is up to 41.5 cm.

The redeye piranha occurs in the rapids but is also captured in deep zones of main rivers with the use of fish bait. Is essentially a carnivore, feeding on small fish, crabs, mammals, lizards and coleopteran insects. Its opportunistic behavior allows it to adapt to various biotopes. It is timid and not aggressive but it possesses powerful dentition that can cause serious bites, and is therefore, potentially dangerous. Import is prohibited in some areas. However, the incorporation of this species in fish-based house security systems has been proposed

Piranhas live in very diverse habitats ranging from soft blackwater, to hard whitewater areas in the amazon, and as such, are very tolerant of differing water chemistry.

There are several variations of this species depending on the collection spot. Peruvian S. rhombeus are called jet black highbacks ( Niger ). S. Rhombeus from Brazil are mostly lightly coloured and some have diamond shape scales. Venezuelan S. Rhombeus have the brightest red eyes and grey coloration.

[edit] In the aquarium

It is generally recommended to keep no more than one in captivity, as redeye piranhas generally do not tolerate ANY tankmates, particularly when they are adults. In the wild it is believed that they generally form loose shoals (or schools, but seem to join and leave different shoals at will). Their primary source of food at a juvenile size is the fins and scales of other fish. In captivity it is possible for them to reach a size of up to 12". It is rare to see them at this size, however, as their growth rate is generally very slow. Specimens that are in the upper size ranges can command very steep prices (such as $500 for a 12" fish). In the aquarium they should be fed a varied diet. Many people feed beefheart, and recipes for mixtures abound on the internet. Feeding live food is controversial.

They do, like all piranha, have razor sharp teeth and powerful jaws and caution should be used when performing tank maintenance, particularly when they are of a mature age. They are much bolder and aggressive at an older age. Juveniles are on average fairly timid. Individual animal temperament does of course vary.

As with any aggressive species, a close attention to water parameters (i.e. ammonia, nitrates) is important, as they are very messy eaters.

All Serrasalmus species are solitary piranhas and S. rhombeus is no exception. They must be kept alone.