Pacu
Piaractus mesopotamicus
Also known as: Paraná Pacu, Paraná River Pacu, Small-scaled Pacu
A seed-crunching giant from South American floodplains that outgrows almost any home aquarium.
About
Found in the Paraguay-Paraná River basin of South America, Piaractus mesopotamicus is a large, deep-bodied fish closely related to the pacu and, more distantly, to piranhas. Its robust, laterally compressed frame and powerful jaws are no accident. In the wild, adults push into seasonally flooded forests to forage on fallen nuts and seeds, a feeding strategy that has shaped its blunt, molar-like teeth and hearty appetite. In the aquarium it accepts a wide range of foods readily, which partly explains its beginner-friendly reputation, but that label comes with a serious caveat: this fish grows large, and it grows fast. Reaching close to 20 inches at full size, it demands a tank that most hobbyists simply cannot provide at home. The 250-gallon minimum is a genuine floor, not a conservative estimate. Keepers who can accommodate the space will find it a personable, active fish with real character. It tends to be peaceful toward similarly sized tankmates and does not show the aggression you might expect from something with such impressive dentition. If you are considering one as a juvenile, go in with a long-term plan. This is a fish that can live over a decade and will not stay small for long.
Similar species
Other fish you might consider
Good tank mates
Species that tend to coexist peacefully with Pacu
From the same region
Share the same natural habitat. Great for a biotope-themed tank
Frequently asked questions
- How big does the Pacu get?
- The Pacu reaches about 12–19.5" as an adult.
- What size tank does the Pacu need?
- A minimum of 250 gallons is recommended for the Pacu.
- What water parameters does the Pacu need?
- The Pacu does best with a temperature of 73–82°F, a pH of 6.5–7.2, hardness around 5–10 dGH.
- Is the Pacu aggressive?
- The Pacu is generally peaceful and suits a community tank with similarly calm tankmates.
- What does the Pacu eat?
- The Pacu is an omnivore. It does well on a varied diet of quality flake or pellet plus occasional frozen or live foods.
- How long does the Pacu live?
- With good care, the Pacu typically lives 8-12 years.