Tropical Fish Site

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Black Piranha – Serrasalmus Rhombeus


Common name: Black Piranha, Rhom

Scientific name: Serrasalmus Rhombeus

Average Adult Fish Size:  12 inches  /  30 cm

Place of Origin: Primarily Guyana.

Typical Tank setup: Open swimming space is essential for this active tropical fish. Some boulders and more bogwood, maybe some plants although these run the risk of being damaged so plastic plants could be preferential.

Recommended Minimum Aquarium Capacity: 110 gallon / 450 litre

Compatibility: Extremely aggressive tropical fish and should only really be kept on it’s own as a single specimen in it’s own tank, mix with other fish or more than one of them at your own risk!

Temperature: 72 – 82 Deg F / 22 – 28 Deg C

Water chemistry: pH 4.5 – 7.5

Feeding: Once acclimatised juveniles relish live or frozen bloodworm, Tubifex, Artemia, chopped prawns and similar foods. Adults should be fed correspondingly larger items, such as whole mussels, cockles, prawns, chopped squid, whitebait and earthworms. Once the fish reaches adult size it need only be fed two or three times a week.

The Black Piranha should not be fed large amounts of mammalian/avian meat such as beef heart or chicken. Some of the lipids contained in these meats cannot be properly metabolised by the fish, and can cause excess deposits of fat and even organ degeneration. Similarly there is no benefit in the use of ‘feeder’ fish such as livebearers or small goldfish which carry with them the risk of parasite or disease introduction and at any rate tend not have a high nutritional value unless properly conditioned beforehand.

Sexing: No external sexual differences between the sexes have been recorded although females in spawning condition are usually plumper than males.

Breeding: Huge amount of water/pond required to breed the Black Piranha in the home aquarium, very little known about breeding outside of the wild. Keeping more than one specimen normally ends in fighting to death anyway so attempting to breed is not recommended.

Additional Information: Although the Piranha as a fish has a reputation of being aggressive, the most common Piranha in the fish keeping hobby is the Red Bellied Piranha, this is because it is possible to keep more than one on it’s own in a tank and so is more of a spectacle in the home. Due to only realistically being able to keep a single Black Piranha in the home aquarium and a large one is required this could only be seen as a pet and very few would want such a large “empty” tank. The Rhom does however live up more to the traditional perception of the Piranha fish species in it’s level of aggression and toleration of other fish.