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Black Piranha

Serrasalmus rhombeus

Freshwater South America

A formidable solitary apex predator boasting intense red eyes, jet-black adult coloration, and immense crushing bite force. Unlike schooling piranhas, this species is fiercely intolerant of conspecifics and must almost always be housed strictly alone in a large aquarium.

Also called: Redeye piranha, Black piranha, Caribe amarillo, Piranha.

35 cm adult length, drawn to scale. deep body.

Outgrows a typical home tank. Check this fish against the adult size above before buying a juvenile. The minimum shown is the least it is kept in for good, not a comfortable size.

Try it in the planner Opens a tank sized to its minimum with 1 fish added.

What it needs

ItemValueBecause
Adult length 35 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 500 L, at least 150 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 200 L estimated What each further fish adds once the minimum is met.
Waste load Class 5 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 24 to 28 C Stock sharing a tank need overlapping ranges.
pH 5.5 to 7.2 Compared with tankmates in the Water check.
Hardness GH 2 to 12, KH 1 to 6 Degrees of general and carbonate hardness.
Flow Medium Low-flow fish are stressed in a strong current.
Light Dim Matched to the lighting class on the needs sheet.
Group size Single fish is fine Not a schooling species.
Temperament Predator Territorial: strong.
Swims in Middle water Fish that use different levels share a tank more easily.
Lifespan About 20 years A fish is a long commitment.
Experience Some experience helps A guide to how forgiving the species is of mistakes.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Black Piranha is an carnivore that swims in the middle of the tank. It is safe with plants. Give it some cover. It will eat fish small enough to swallow. It nips fins.

Tankmates

Works with

No close matches in the data. Check the pair tool.

Depends

Nothing flagged.

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.