Serrasalmus rhombeus

Common Names: Black Piranha
Niger Piranha
Rhom Piranha
White Piranha
Synonyms: Serralamus niger
Family: Characidae
Category: Characins
Distribution: America - South; Located mainly throughout the Amazon and Orinoco river systems
Main Ecosystem: River; Lives mostly in fast flowing part of the river but, is caught in deep water places
Temperament: Territorial; Unlike their fearsome reputation the black piranha is not a all out killer. They're very skittish and shy. They will still however kill any other tank mates.
Diet: Carnivore; Like most other piranhas the Rhombeus is a carnivore. The most common diet is goldfish and other live fish. However it is not the best. Fish fillets, whole frozen smelt, and earthworms and good for older fish. Bloodworms and brine shrimp and good foods for smaller rhoms.
Care: Care is very simple. Smaller rhoms can be kept in a 20-30g till there about 4"-5". It should be then transferred to a 55g or 75g. This will be a good tank for a very long time considering the growth rate after 6" is 1/2"-1" per year. Once/if it hits 14" a 120g/125g would be good for the rest of its life. There are 2 key factors in growing out a large rhom. A powerful current and a automatic drip system. Rhoms live in fast flowing rivers with lots of current, this current makes them expend energy
6.5 - 8
23°C - 27°C
73°F - 81°F
10 dH - 20 dH
Potential Size: Male: 40cm (15.7")
Female: 40cm (15.7")
Water Region: Middle; Middle
Activity: Diurnal; Diurnal
Gender: There are no sexually dimorphic signs. There have been reports from a biologist from south America that rhoms with higher backs maybe females, but this is just a theory.
Breeding: Breeding is basically non existent in captivity, due to the rhoms intolerance of tank mates especially other rhoms. However in a few rare cases public aquariums have done it, but no specifics has been released.
Comments: A very interesting fish to keep. They can be very beautiful especially the diamond varieties. They can be dangerous but using common sense any incidents can be avoided. Larger rhoms are very valued fish, with 16"+ rhoms going for $500 plus. There are 2 main varieties, the regular black rhom and the diamond rhom. The diamond has a few color variants such as black, gold, and the rare blue.
Main Colours: Black, Silver
Markings: No Markings
Mouth: Normal
Tail: Concave
Search: Show similar species
Find compatible species
Image Credit: ©
Submitted By: greenmonkey51
Contributors: weird22person
History: View changes to this profile
Edit Profile: