For the sake of the club and what information we need, I will keep this as simple as possible. There are many people out there that have a far stronger knowledge of the different genus that make up the Piranha world and the species within those genus, but as this website is based around the fun involved in keeping Piranha, I will keep it brief and to the point and will only cover the most popular of the home kept fish. I am happy to say that currently, between our club members, we hold all of the fish species I will mention and some have others, which they will contribute data about.

The two main genuses are the Pygocentrus group of fish and the Serrasalmus group. There are large and obvious differences in these two groups of fish, the main one being their general look. The Pygocentrus having the blunt “bulldog” features so commonly associated with Piranhas, where as the Serrasalmus breeds have a much longer, pointed face and streamlined structure.


There are four main fish within the Pygocentrus genus and they are as follows:-

1) Pygocentrus Nattereri (Red Bellied Piranha). This fish is probably the most common of the Piranha species for the home fish keeper. They can be easily purchased in aquarium shops in the UK and do not cost very much. One of the main reasons that this fish is so readily available is the ability they have to breed in captivity. This of course then cuts out the need of importing them from South America and in turn, keeps the cost of the fish down. The P.Nattereri is a good starter fish for the novice Piranha keeper as they are fairly hardy and put up with differing water conditions. I started my love of keeping Piranha with P.Nattereri and am ashamed to admit that they went into a tank that had not been cycled and had only had the water in it for a day, but they did very well, grew 4 inches in no time and had wonderful colouration. But please remember, it does not matter if you are keeping P.Nattereri or P.Piraya, you should always properly cycle your tank before introducing fish.

The Fish is found in both the Peruvian and Brazilian Amazon. An average adult can reach the length of 12”. They are a good shoaling fish so an ideal Piranha to keep in home Aquarium but should not be kept in groups smaller than three or four fish. In the home aquarium, they are often known to be slightly shyer than their relatives listed below, but this can also depend on the housing etc that you have provided for them.

2) Pygocentrus Caribe (Orinoco Red Bellied Piranha). Again, this fish is another good fish for the slightly less experienced Piranha keeper, although they are more active and less skittish than the P.Nattereri. I personally have not heard of this fish being available through a UK aquarium shop before, although I did hear that there was a place in the North of England that did import them some years ago. This fish could be mistaken for the P.Nattereri as it is very similar in shape and colour. The biggest difference with the P.Caribe is the large black spot behind their gill plate. As I mentioned, they are a brave fish and have extremely powerful jaws and sharp teeth, so should be treated with care if transporting from one tank to the other or handling in any way.

The fish is found in the Orinoco drainage of Venezuela. An average adult can also reach 12” in length. Again they are a good shoaling fish and can be kept happily in groups and also mixing with others from the Pygocentrus family. The name Caribe comes from a group of Indians by the same name who were know for their cannibalistic ways. The fish were given this name, as they will turn on members of their own shoal who are sick or injured, and eat them.

3) Pygocentrus Piraya. This is not really a fish for the beginner. Again, these fish are not available in aquarium shops in the UK and when imported from abroad, are very expensive. This Piranha is known by many as the King of Piranhas. It was a beautiful golden stomach and blunt nose leading down to powerful jaws. There are many stories from people lucky enough to own P.Piraya that they are difficult to keep in captivity mainly because they require near perfect water conditions and are often very violent to their tank mates. They have enormous appetites and need to be fed regularly otherwise you will loose other Piranhas. Others state that as long as they are not in overcrowded tanks and are introduced to the tanks when young, that they will be fine.

The fish is found only in the Sao Francisco river in Brazil. The size of a fully grown adult seems to be a topic for much discussion, but they are reported to grow to over 20” in length so only a very large tank should be provided if you were to consider keeping a shoal of P.Piraya.

4) Pygocentrus Ternetzi (Yellow Emperor Piranha). I have kept this Piranha till last as there is much debate over if Terentzi actually exist. This is one of my personal favourite fish and one I am lucky enough to have a small shoal of. They are similar to their cousins in the fact of the blunt head, powerful jaws, thick set with broad shoulders and a good shoaling fish but they have a lovely yellow underside. Some people say that the sides of this fish look like they have been sprinkled with diamonds, as the fish glitters when it moves. When I speak about the actual existence of Ternetzi, it is because many people believe it is actually a P.Nattereri but just from a different area of South America. No scientific proof has been made to say they are an independent breed as yet, but many experienced Piranha keeper has also pointed out the main differences between Nattereri and Terentzi including a much more prominent lower jaw, broader set shoulders and generally, much braver and charismatic fish. Many believe the name Ternetzi is one simply made up by the hobbyist and has no scientific value. The arguments will go on for some time but it does not take away that these fish are great.

The fish is found in Argentina and is reported to reach 16” when fully grown, although there is speculation that it grows larger. Happiest in shoals over 3 fish and needs large housing. Like all its cousins above, should be handled with great care due to the large teeth and powerful jaws. Again, this fish is rarely if ever, found in UK aquarium shops.


The five main fish within the Serrasalmus genus are as follows:-

1) Serrasalmus Rhombeus (The Black Piranha). The S.Rhombeus, better known as the Rhom, is a great fish to keep. They have the pointed features associated with the Serrasalmus genus leading up to a thick high back under the dorsal fin. The fish has amazing red eyes, which it is famous for and is a legendary eater. The S.Rhombeus is not a particularly difficult fish to keep but must be kept on its own, so if you are looking to keep a solitary fish, this is your boy. The main reason is that this fish does not mix with any other fish, including it’s own breed. They will attack and kill any other fish in the tank. Because of this, they are a very popular fish for the hobbyist to keep but will need large housing due to their size. The fish changes it shape and colouring a lot from when it is young and silvery with some spots, to a fully grown specimen being almost black with purple flecks and ruby red eyes. Some of these fish do turn up in UK aquarium shops, but it is rare.

The fish is found all over the Amazon and Orinoco waterways and can grow to 18” in maturity. Again large housing will be needed if the fish is to grow to this size and an adult S.Rhombeus can easily amputate a human hand at the wrist in 2 or 3 bites, so be careful.

2) Serrasalmus Brandtii (Golden or bronze Piranha). Next to the S.rhombeus, this must be the most aggressive of the Serrasalmus genus. Similar in some ways in apperance to the other Serra’s, this fish can only be kept on their own as they will attack anything in the tank including nets. I own a S.brandti and can say from personal experience that he will constantly try to attack me though his glass and is very active. S.brandti comes from the Sao Fransciso area of the Amazon alongside P.piraya. They are very rare and hard to get hold of mainly because of the remoteness of their enviroment which needs the fishermen to take long journey’s up to this part of the river and it’s tributaries.

3) Serrasalmus Elongatus (The Pike Piranha). This fish has the most streamlined and shallowest bodies of any of the other Piranha species. It is built for speed, mostly ambushing its prey from behind cover. The long mouth has ferocious teeth lined inside and it simply strips away at its prey. Again, the fish is a solitary fish and can only be kept on it’s own as it does not tolerate tank mates. It is also know to be one of the bravest Piranha and will literally follow you around the room from it’s tank, and dive bomb the glass if you come near. They are hard to come by, completely nonexistent in the UK, but are a prized possession (two of our members are proud owners or Elongatus from one of our imports).

Generally found in the Peruvian and Brazilian Amazon and in Venezuela. Is not thought to grow so large but 9” is a specimen fish.

4) Serrasalmus Spilopleura (Red Throated Piranha, Ruby Red Spilo & Gold Spilo). This fish is a very common hobbyist Piranha and comes in several different colour variations as I have listed above. They are known to be fairly shy. When young, these fish are spotted and pointed faces, but become deeper bodied and blunter faced as they grow up. They are not as voracious as their two cousins above, feeding mainly on fish fins. They can be kept together in small shoals although fin nipping will be a problem.

They are found all throughout the Amazon river and it’s tributaries. An adult will reach 7 – 8” in length and these fish can be found in some good aquarium shops in the UK.

5) Serrasalmus Manueli (Manuel’s Piranha). A very attractive fish and not so common at the moment in the home aquarium. They have a similar black spot or band as the P.Caribe and their gill plates are often golden yellow mixed with red. Not a great deal is know about these fish other than they feed on both flesh and plant matter.

They are found in abundance in the Orinoco drainage and can grow up to 13” but their cousins in the lower Amazon are known to get bigger. A fish that will become very popular in the future for Piranha keepers.

6) Serrasalmus Irritans. This is probably the smallest of the Serrasalmus genus. The fish have small dark spots on the upper part of their bodies and an attractive red anal fin. They feed mostly on fins, which sometimes makes them difficult to mix together and shoal.

S.Irritans are found in the Savanna areas of the Orinoco drainage. They will not grow much larger than 7”.

Edited By Nick