TankMatesTankMates
Sign in
Encyclopedia / Oddballs & Predators / Red-bellied pacu
★New · no ratings yetPhoto

Photo, CC0 · source · credits

Variations

1 kinds · tap one for a closer look

Red-bellied pacu

Piaractus brachypomus · Pacu, Vegetarian piranha

Calm but enormous.

Local price coming soon
· real AED shop prices, never conversions
88 cmAdult size ✓
23–28 °CTemperature ✓
6–7.5pH ✓
2550 LSmallest tank ✓
Add to my tankCompare
Tank mates
Check your own mix →
Not recommended
  • Red-bellied pacu eats animals up to about 12 cm. Neon tetra only grows to 2.5 cm.
Not recommended
  • Red-bellied pacu eats animals up to about 12 cm. Cardinal tetra only grows to 3 cm.
Not recommended
  • Red-bellied pacu eats animals up to about 12 cm. Black neon tetra only grows to 3.2 cm.
With conditions
  • Rift lake cichlids like peacock cichlid need hard, alkaline water and a busy, cichlid-only tank.
  • Only a narrow pH range suits both: exactly 7.5.
With conditions
  • Rift lake cichlids like frontosa need hard, alkaline water and a busy, cichlid-only tank.
  • Their pH needs don't quite meet (6–7.5 vs 8–9). Aim between the two and keep it steady.
Compatible
Compatible
Compatible
Compatible
Compatible

166 species in our list are a good match.

Facts checked against sources on 16 Oct 2026. ✓ means a source backs it; ? means no reliable source yet. See sources

Care and water

Hardness ✓0–15 dGH
Group size ?Can live alone
Temperament ✓Peaceful
Swims at ?Middle
Care level ✓Hard
Diet Omnivore
Lifespan ✓20–28 years
Size in shops 5–8 cm
Growth Very fast

Behavior

Calm but enormous.

Not for home aquariums. This fish grows far too big for any home tank. It needs a pond-sized system of thousands of litres, so please don't buy one as a baby.

Good to know: Sold tiny, often labelled "vegetarian piranha", but reaches 80 cm and 25 kg.

Food

Pellets, fruit, vegetables.

Tap a food to see what it is.

Male or female

Mature females are a little rounder-bellied than males; juveniles cannot be sexed.

Health

Common problems. Tap one to see the signs. This is a guide, not a diagnosis.

Breeding

Rarely bred in captivity ·

Not bred in the hobby; bred in numbers for food on farms using artificial (hormone-induced) spawning in ponds. In the wild it makes seasonal spawning migrations.

Pairing

Adults in ponds.

Setup

Ponds.

What starts it

Hormones.

Eggs

Females scatter adhesive eggs that are fertilised externally; no egg count found.

Raising the fry

Live food.

Common mistakes
  • Space
  • Aggression
  • Escape
Full breeding guide, day-by-day plan and simulator →

Where it lives in the wild

RegionAmazon and Orinoco basins
Rivers and lakesAmazon and Orinoco rivers
HabitatFlooded forest
Native rangeAbout 2,000 km across
See it on the world map

The story of the red-bellied pacu

Has cusped teeth that resemble human molars, used to crush fruit, nuts and seeds. Often sold as 'vegetarian piranha'; aquarium releases have left populations in the USA and elsewhere.

Georges Cuvier described this pacu in 1818. Juveniles have a red belly and are often sold looking like piranhas, but adults become large, mostly plant- and fruit-eating fish. It is also important for fisheries and fish farming in South America.

First described by Georges Cuvier in 1818.

  • Its teeth look like human molars.
  • It eats fruits and seeds.
  • It can grow to over 80 cm.

Sources

17 facts checked with sources