Red Bellied Piranha Caresheet and Information

Red bellied Piranha

Red-bellied piranha Care and Pet-Keeping Information Care Sheet

The red-bellied piranha (Pygocentrus nattereri) is a species of piranha. The red-bellied piranha has the reputation for being one of the most ferocious freshwater fish in the world. Their set of razor sharp teeth are capable of stripping flesh from prey and dead animals. As their name suggests, they have a reddish tinge to the belly when fully grown, although juveniles are a silver colour with darker spots. They grow to a maximum length of 33 centimetres (13 in) and a weight of 3.5 kilograms (7.7 lb) . The Red Belly is the most common of all piranhas.  It has very powerful, sharp teeth that continually replace.  Although Red Bellies have a reputation for fierceness, they are actually fairly timid, nervous and inactive, except when hungry.

They will play dead when frightened.  The distinctive feature is the red belly, highlighted against a silver/grey body. Determining the gender of piranha’s is considered almost or all together impossible by most piranha experts, because there are no visible differences between the genders (in other words, piranha’s are not sexually dimorphic). The general consensus is that the only more or less fool-proof method to sex piranha’s is to observe them during spawning.

Young Redbellied Piranha’s are silver in color, their body covered with small black spots. The shape of the head is much more concave than adults and they have very large eyes. The growth rate remains high until the fish reach a length of about 4-6 inches: by then, the fish are about 12 to 14 months old, depending on the circumstances they live in: tank space, diet, water quality, the stress factor, the presence of water current from a powerhead.After that, a Red Bellied Piranha’s growth slows down to about 1″ per year (and even less once they hit the 9-10″ marker) and reach sexual maturity when then are between 18 and 24 months old, once again depending on the factors mentioned above. The older the fish, the darker it will get. Some specimen will almost completely loose their red belly and turn completely pitch black, sometimes because of old age, sometimes because of stress, and sometimes to signal they are ready to spawn.

Red-bellied piranha is native to:

This species lives in the Amazon River Basin, coastal rivers of northeastern Brazil, and the basins of the Paraguay, Paraná and Essequibo Rivers.

Red-bellied piranha’s average lifespan:

Life Span: 12 years

Red-bellied piranha’s average size:

 A  Red Bellied Piranha’s growth slows down to about 1″ per year (and even less once they hit the 9-10″ marker) and reach sexual maturity when then are between 18 and 24 months old, once again depending on the factors mentioned above. The older the fish, the darker it will get. They grow to a maximum length of 33 centimetres (13 in) and a weight of 3.5 kilograms (7.7 lb) .

Red Bellied Piranha enclosure and housing:

The tank should be about 100 gallons and should hold about 5 piranhas (2 gallons per inch of piranha).  The tank should have driftwood and dim lighting. Soft, acidic water preferred.  Live plants will help to remove excess nitrates and CO2 from the water.  A strong filter waterfall type filter is recommended. Under gravel filters are not a good idea, as the less your hands are in the water, the less stress they will be under, and lessen the likelihood of a nasty bite.  We have 2 in a 55 gallon, and they seem to fight a bit every now and then for dominance in the tank. A min. of 3 in a tank will help to prevent this. A tank containing red-bellied piranha should be kept at a constant pH of 5.5 to 7.0, and water parameters of nitrate, nitrite, and ammonia monitored at least every week. Furnishing the aquarium with bogwood (mangrove root, e.g.) has been suggested to assist in keeping the pH constant.

*Note* Be sure to boil any and all bogwood you place into the tank, regardless for where it was purchased or found.* We used some freshwater driftwood and heated it in the over at 200 F. for 1 1/2 hrs.

The safest tank mates you may consider putting in the tank are mystery snails. The fish seem to just look at them like a moving rock. They also will help to clean the sides and substrate of algae and left over bits.  This is not to say that they are a substitute for water changes and good maintenance of the tank. No salt should be added to the tank at all. You may hear about aquarium salt being good for fish, but, in this case, don’t use it. They are from an area that has no salt in the water, and will harm or kill your friends.

Temperature Range 73°F – 81°F
pH Range 5.5 – 7.5
Hardness 15° – 20°

Red Bellied Piranha substrate:

The ideal substrate is small to med rock, an inch or so deep, with enough to properly anchor any live plants you may wish to use. Be aware that regardless of how you may set up the scene in the tank, they will redecorate the way that they want things.  Piranha like caves and large plants to hide behind. Softened light is needed to reduce stress as well. A simple red or orange filter under the lighting works well. Be sure that if you use a filter for the light, that it will not ignite or melt.  Florescent light fixtures are the coolest in temp and work well, for both the tank and any plants. As these fish are native to murky and dark waters, the closer you can replicate the Amazon river bottom, the better and less stressed they will be.

Red Bellied Piranha heating and temperature requirements:   

Keeping them in a shoal of at least 3 fish (the more, the better), dimming the lights and using blackwater extract, (Activated carbon will remove the extract) or peat in place of carbon filters to mimic the murky waters of their original habitat, providing adequate places for them to hide (rocks, bog wood, plants), raising the water temperature, adding a potent powerhead to the tank, and placing the tank in a high traffic area are all suggested as the solution to decrease skittishness of the Red Belly Piranha, but unfortunately there is no guarantee any of these measures will work. 75 to 82 F is ideal. The more plants and hiding places, the less stressed they will be.  These fish, particularly when juvenile, will sometimes bite one another in the aquarium, normally on the fins, in behaviour called ‘fin nipping’. Fish that have had their fins nipped will grow them back surprisingly rapidly. These fish can be timid in the aquarium, in contrast to their reputation. This can be for a variety of reasons, i.e. due to unnaturally high light conditions, poor water quality, and lack of cover, which juvenile fish in particular need to hide.

Red-bellied piranha’s feeding:

When feeding, the Red Bellied Piranha is an aggressive meat eater that swarms on prey in large schools. They often nip fins and flesh without killing their prey. The Red Bellied Piranha is strictly a meat eater. Care should be taken to ensure feeder fish are free of disease.  Placing meat products in the aquarium will be appreciated by the piranhas, but will quickly foul the water.  Captive Red Belly Piranha can be taught to eat almost everything meaty, ranging from feeders (goldfish although not recommended, rosy reds, minnows, tetras, basically anything small enough), frozen fish (smelt, cod, catfish, salmon, tuna fish etc.), shrimps, krill, mussels, squid, insects and even small mammals (pinkies, mice….), reptiles and amphibians. Some owners have ‘learned’ their piranha’s to eat food items such as dog and cat food (Not recommended as the fat and oils can harm the fish and make the water quality poor) , cheese, fish flakes and pellets, and even seeds vegetables (such as cucumber), and fruit. Others make their own food cubes by blending different ingredients, ranging from pellets and food supplements designed for aquarium fish, to vegetables and meat, mix it with gelatine, and freeze it.

If you wish to feed live fish, we recommend using minnows (Available at any bait shop) as they are “bite size” and foul the water less. You will need to set up a separate tank for the minnows and be sure to filter it well.  Piranha will eat dead and dying fish as well, but you must be sure to remove any left over after 6 to 8 hrs to prevent the water from becoming cloudy and the gravel clean.

Red Bellied Piranha Handling :

The Red Bellied Piranha is an aggressive meat eater that swarms on prey in large schools. They often nip fins and flesh without killing their prey.  If they are hungry, they will attack your fingers. Most times they will flee, but if cornered, they will defend themselves with aggression. When cleaning your tank, use a long handled scrubber and a long vacuum tube to ensure that any nips will not be out of you.


Breeding in captivity is difficult at best. Unless you’re an aquarium or expert, leave it to the pros. This requires a huge tank and specialized care of the fry and juveniles.  Also, as these fish are banned in 20 states, you will need to check the laws regarding them and any ordinances in your area. See the Law and Piranhas. They will make for an exciting and interesting addition to your home. High maintenance and skittish, these fish are not for the novice and require special care, but with time and care, they make for a great bit of oddity. As with any exotic type of animal, these must be purchased from a reputable breeder or pet store.  These are NOT a cheap fish to own or maintain. Their diet and high maintenance makes them a fish for those with the time and money to keep.  Too often people purchase these guys because of their reputation, and end up dumping them into local ponds and lakes, where as an introduced species can and will quickly become a problem in the ecosystem.  Again, if you don’t think you can handle or want the responsibility of their care, don’t get them. Be responsible, if they get too big, or you can’t keep them. Call an aquarium or local pet store or shelter that can handle them, to have them removed or re-homed.


  1. Edgar Martinez says:

    I have two young RBP’S and I was wondering if adding fresh water sand to their tank would be a good idea?

    1. Stephanie H says:

      As they are freshwater fish, fresh water sand would be just fine. You can use either gravel or sand or a combination of both for their substrate, as they don’t filter through the sand and there is no danger of ingesting it. It’s all a matter of personal preference, some people like the look of sand, and find it is easier to clean than gravel, but it is up to you! Also, sterilized driftwood or Mopani wood (which leeches natural tannins into the water which are great for Piranhas) make great decorations no matter whether you choose sand or gravel.