Terrifying Carnivore

The Red-Belly Piranha is easily one of the most feared fish in existence

by Mike McEwan

Red-belly Piranhas are large, flesh-eating characins. They have a reputation for attacking in large shoals and stripping flesh from any creature that enters the rivers in which they inhabit. Many stories are exaggerated, however. It is recommended that if you are looking to purchase such a magnificent fish, you learn as much as possible before committing to keeping this carnivore. Piranhas are often bought by beginners looking for a quick thrill, and often the fish disappoints. In warmer states it may be illegal to keep a Piranha because of the number that get released into local water systems and take over all other forms of life.

This deep-bodied fish varies in color, both with age and environmental conditions. Younger specimens are blue-grey along the back with delicate olive green flanks and numerous siver-metallic spots that give the body a nice appearance. As the fish mature, they tend to fade in color.

These fish are unsociable, especially when confined for transportation, and will pick on each other, causing considerable damage to the body and fins of others. It is not uncommon to see body parts missing from Piranhas that are provided with little space to swim, as they will turn on each other.

When buying Red-belly Piranhas, select a shoal of small, young specimens and allow them to grow up together, forming their own hierarchy within the shoal. Provided this is not disturbed by adding more piranha at a later date, the shoal should flourish.

Tank Setup

Red belly Piranhas can get frightened easily and appreciate sheltered areas in the aquarium, provided by large plants such as the Amazon Sword, and pieces of bogwood. To see the piranha at its best, allow natural sunlight to fall on the tank. In reflected light, the highlights and metallic shines on the flanks of a mature, healthy specimen are magnificent. Light levels should be dimmed, however, through the use of floating plants.


Piranhas are carnivorous and should be fed accordingly. Many specimens will accept nothing less than live foods such as earthworms or fish. Prepared foods such as chopped beef heart and fresh beef may also be accepted. Do not trust the fish with your hand in the tank, especially during feeding times.

Water Chemistry

Water conditions are important. These active fish require high levels of oxygen and good water flow, so external power filters or a powerhead are a must. The water should be slightly acidic, with a pH of around 6.4-6.8. In hard waters, the fish do not show such intense coloration. Keep the temperature between 75 and 81 F.


Sex differences and breeding behavior are not known for Red belly Piranha (although they have been bred by the thousands in Hong Kong), but another species, Serrasalmus spilopleura, has been reported to spawn in the cichlid fashion.

Red-Belly Piranha

Sci Name:
Serrasalmus nattereri
The Parana river
Max Size:
Slightly Acidic
75-81 F.
Tank Size:
55 Gallons

Copyright © 1998 Aquaria Central. All rights reserved. Reproduction in whole or in part in any form or medium without express permission of Aquaria Central is prohibited. Full copyright notice HERE.