Serrasalmus nattereri have been renamed to pygocentrus (sp?) natterreri, they are the shoaling red belly piranha, rpbs, and are the easiest to get and keep of the piranhas.
Keep them alone or better in groups of three or more , Do not keep just a pair or they fight.
For piranha they grow pretty quickly until about 6 " then slow down, they usually reach 9-10" but I had one that got to 14". Keep in standard tropical conditions, temp 78-82F, ph near nuetral or slightly acid, it is not real critical but they do better if the water is soft and not alkyline. They like planted tanks but do occasionally prune the plants so use cheap, fast growing ones. They are true carnivores and messy eaters, they readily adapt to meaty foods, feeder fish, live and peeled raw shrimp, clam meat, beefheart, earthworms, crayfish (trim the thumbs first), and any good carnivore pellet, they also like live crickets or grasshoppers. A varied diet is a good thing. They are a bit sensitive to copper in foods and meds, they get pale and skinny from it. For adults you will need at least a 200 liter tank for 3, a 300 liter tank would let you keep 5-6.
Except when feeding they tend to just hover rather than cruise the tank.
Good luck with them.
By the way, if I have not said so before , welcome to MFK.
eg har samme sorten, hvor store er dine? husk at dem er veldi redde no når dem er små og vil for det meste ligge og gjemme seg i skyggen, men dette vil avta når dem blir større.
