I've had piranhas for about 10 years now and have had success with feeding them a high quality dry dog food. I've never bought feeders since, except for the odd show to my friends
Not one person has mentioned the very real fact that it is illegal in most states of the United States to keep piranhas in home aquariums. If you are American, you must check with your local fish and game department or chance a substantial fine if they find out you have one in a state where it is illegal. This is because in the past, irresponsible hobbyists have thrown unwanted or "tank outgrown" specimens into waterways near their homes and forgotten about them, which can wipe out nearly every native fish species and create havoc in a biotope in which it does not belong. Please be responsible and check in your state to see if it is legal. You may be suprised. I live in the state of Vermont which is one of the FEW states where it is legal. Many pet shops can get this fish even though it is illegal in their state. They are sometimes placed on the invoice as baby pacus, which they resemble greatly. Just a little FYI for folks who didn't know. I work in a pet shop. This is how I found out, besides reading fish mags.
Yeah, Piranhas are illegal in most of the southern states in the US. I heard rumors a few years back about Piranha being found in Lake Okeechobee in Florida. Supposedly some cattle were killed or something like that. Also, I think the walking catfish is also illegal in Florida, but that's another fish. Supposedly they adapted to the southern swamps and can be seen walking from pond to pond! I wish I could obtain them legally, I've always wanted to see what these fish were all about. The best I can do here are Managuese Vampire Fish which are pretty lively but not as aggressive as I've heard Piranhas are. I guess I'll have to move up north if I want to raise them.
I have had two Piranhas for about two months now. I started feeding them pellets at first, then I started as they grew to feed them live fish and frozen fish bait. Now they are flesh eating animals and try to take off my fingers. It is really cool, however cleaning the tank can be time consuming.
I don't claim to be an expert by any means, but I have kept a Piranha successfully with other fish. I purchased the little guy when he was about 3 cm long. He was first kept with a similar sized silver dollar. When he was about 8 cm long, I put him in a larger tank with an African Snakehead, two Jack Dempseys, and a Tinfoil barb. Believe it or not, the Snakehead was by far the undisputed ruler of that tank for as long as I had them together. The Piranha "buddied" up with the Tinfoil Barb, and the two would continuously school together. The Piranha would eat goldfish and was always nipping the Tinfoil Barb, but he didn't do any serious damage. I think he learned that only goldfish were food. These fish were not together for a long time, because they all got fairly large.
I've been collecting freshwater fish for maybe 30 years now. I get a huge kick out of the more dangerous or misunderstood specimens, and most recently I keep a pair of Serrasalmus nattereri piranhas from Peru. I put them in a 260 L tank with some feeders for company, a heavy branch, and some amazon swordplants which are suffering from their attacks on the feeders that try and hide there. I get a huge kick out of these little fellas; they are very cool. Also I feel kind of sorry for them, they are like the ugly kid on the block that nobody wants to play with. Recommendations? I'd say "healthy respect" is a good by-word. No sense in acting brave to impress your friends and then losing a finger in the process. Also, try an resist the temptation to feed with pork, beef, and other greasy raw foods. These fish are meat eaters in nature, but that means FISH meat, which is very lean. They only eat red meat if they are starving, like after a draught. If you feed them fatty foods like steak or ground beef, pretty soon their water will stink like hell and you'll have all kinds of fungus and rot, so please resist the temptation.