Meet the Zoo: Piranha

Almost everyone has seen a flashy video clip of frenzied, sharp-toothed piranha amassed around some unidentifiable object; bubbles swirling and clouding the lenses and close ups of tiny sharp teeth in gaping open mouths. It is usually a piece of film carefully edited to enhance the fierce reputation of these freshwater fish.

The Wildlife Conservation Society’s features both red bellied and orange bellied piranha in its beautiful Flooded Forest exhibit. The exhibit is representative of an area in the Amazon River Basin which stretches from northeastern Brazil to Paraguay. As scavengers, these fish play an important role in the ecology of their river systems.

In the Flooded Forest exhibit, keepers feed the piranha with fish skewered onto artificial vines that are lowered into the water. Visitors are often surprised to see the fish feed – not in a rolling, frenzied group, but timidly swimming up to the fish skewers and taking small, almost delicate nips.  Given their reputation, many people are curious about the teeth of the piranha. A single row of sharp, triangular teeth line both jaws and interlock when shut. This allows the fish to puncture and tear off the flesh of their prey.

Not surprising to keepers, these fish are actually very timid and are reactive to changes in their environment. For example, when water levels are adjusted to maintain the proper chemical balance in the tank, the fish immediately swoop to the bottom of the tank practically touching the sand. Once they get the sense that everything is normal, they cautiously return to mid-tank level.

Ferocious or not, the huge fish tank draws visitors in with its beauty. A skylight allows natural light to filter in which creates patterns one might actually see underwater in the Amazon with rays of sun dappling the water. The piranha glitter in these rays as the gold flecks on their skin reflect the light. It is a mesmerizing scene and the piranha’s tank mates provide additional interest. A number of smaller fish flicker about and a beautiful, spotted fresh water ray slithers about on the river bottom. When you hear fellow visitors wonder why the “ferocious” piranha are not in a feeding frenzy, you can smile because now you know the real nature of these quite timid creatures.