Redeye Piranha - in The Aquarium

In The Aquarium

It is generally recommended to keep no more than one in captivity, as redeye piranhas generally do not tolerate 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 35 cm (14 in). 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 30 cm (12 in) 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.

Like all piranha they 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 extremely 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.