Red-bellied Piranha

Red-bellied Piranha key facts

Care level

Advanced

Lifespan

15+ years

Size

About 35-50cm

Temperature

24〜28℃

Diet

Juveniles take bloodworm, small earthworms and chopped prawn; adults take strips of fish, whole prawns, mussels, river shrimp and larger earthworms

Tank

Seriously Fish suggests a base of at least 240 by 90cm, about 648 litres at 30cm depth. Some keepers run a bare bottom for ease of maintenance, though gravel or sand serve equally well. Plants may be eaten, especially when the fish spawn, and lighting can be dim or bright. Adults are known to damage submerged equipment, so choose filters with built-in heaters or fit a sturdy heater guard; a sump also answers well.

Water Temperature & Quality

Seriously Fish gives 24-28C, pH 5.5-7.5 and 2-12 dGH; FishBase gives 23-27C, pH 5.5-7.5 and hardness to 20 dH. The fish produce a great deal of waste, so one or more oversized external filters are considered essential, and 30 to 50 percent of the volume should be changed weekly.

Tank Mates

The image of hunting packs applies mainly to juveniles; older fish live in loose groups and establish dominance hierarchies. A single specimen or a group of five or more is therefore recommended, the latter preferred. It does not suit a community: it will attack sick or failing fish and bite chunks from the fins of larger ones.

Diet & Feeding

Offer juveniles bloodworm, small earthworms and chopped prawn, and adults strips of fish flesh, whole prawns, mussels, live river shrimp and larger earthworms. Never feed mammalian or avian meat: some of the lipids cannot be metabolised and may lead to excess fat deposits and even organ degeneration. Feeder fish bring no benefit and carry the risk of disease.

Breeding & Spawning

It is noted that plant-eating becomes more pronounced when the fish decide to spawn.

Health & Notes

FishBase lists it as IUCN Least Concern and not on the CITES appendices, but classifies it as traumatogenic, that is capable of causing injury, so take great care during water changes or when netting it. It is not on Japan's invasive alien species list, but it must never be released or abandoned. Given its size and the demands of its housing, settle in advance where it would go if you could no longer keep it.

About Red-bellied Piranha

The Red-bellied Piranha is a large South American tropical fish with a silvery body, red belly, and sharp teeth, growing to about 35-50cm - a species for experienced keepers with a large tank.

7 things to know before welcoming a Red-bellied Piranha

1. 1A Very Large Tank

   Adults can grow to roughly 35-50cm, so they need a spacious tank with plenty of room to swim. A cramped setup can cause stress, poor growth, and conflict between fish, so plan your tank size around their adult size from the start.

2. 2Heavy-Duty Filtration

   As predatory fish, they produce a lot of waste and leftover food, which can quickly foul the water. Strong, oversized filtration along with regular water changes is essential to keep water quality stable.

3. 3Beware Sharp Teeth

   Each jaw carries a row of triangular, razor-sharp teeth backed by a powerful bite. Keep your hands well clear during tank maintenance and feeding, and always handle this fish with care.

4. 4Opportunistic Omnivore

   Despite their fierce reputation, they're actually opportunistic omnivores that will eat whatever is offered. A varied diet of prepared foods, fish meat, and crustaceans works well.

5. 5Careful Tankmate Choices

   Depending on temperament and appetite, they may attack tankmates, so mixing species requires caution. Keeping them alone or only with their own kind, while watching closely, is the safer approach.

6. 6Stable Water Conditions

   As a tropical fish, consistent water temperature is essential. Sudden swings in water quality or temperature can affect their health, so make regular monitoring and testing part of your routine.

7. 7Commit Before You Buy

   Their large adult size and sharp teeth mean ongoing investment in tank size and filtration equipment. Before bringing one home, make sure you're ready for the long-term commitment of keeping them properly.

Frequently asked questions about Red-bellied Piranha

Q.Are piranhas really dangerous fish?

A.They have sharp teeth and a strong bite, so care is needed when handling them. That said, they don't go out of their way to attack people - staying careful during tank work and feeding is generally enough.

Q.Can they be kept with other fish?

A.Depending on temperament and appetite, they may attack tankmates, so mixed-species tanks carry real risk. It's best to keep them alone or only with others of their own kind, and to judge carefully.

Q.How large a tank do I need?

A.Adults can grow to about 35-50cm, so they need a large tank with plenty of swimming room. It's safer to choose a tank sized for their adult size from the start rather than upgrading later.

Q.What should I feed them?

A.As opportunistic omnivores, they can be fed a mix of prepared foods, fish meat, and crustaceans. Keep an eye on nutritional balance and remove leftovers promptly to avoid fouling the water.

Q.Is this a good fish for beginners?

A.The Red-bellied Piranha is considered a fish for experienced keepers. Managing a large tank, maintaining strong filtration, and handling it safely all take real know-how, so it's best to gain some experience first.

Useful tools for Red-bellied Piranha care

Learn more about Red-bellied Piranha in the encyclopedia

More in this category