About a year or two ago I had two 8-10 cm piranhas in the same tank, which was about 100 liters or so. These piranhas picked on each other quite a bit regularly. I thought they were just playfighting. One day I looked in my tank to check out how the two were doing, and I only saw one. I was used to this because there was a large rock that one of them always hid behind. Suddenly there was a shiny object pushed down by the filter. When I looked at what it was I saw where the other piranha was. Actually I could only see where half of the other piranha was. He was missing the back half, still breathing I could see, while my other piranha had a pretty full looking belly. I still have the one that survived and he is a healthy 16-18 cm red belly Piranha.
I have had many piranhas and usually acquired them very small, perhaps 2 cm. At this size they are very nice schooling fish, to which I used to feed chicken livers. The little guys would only eat the inside and sometimes swim all the way inside! When they get larger I feed the usual goldfish but a cheaper way is to buy a couple of pounds of cheap smelt frozen. Then I cut it into small chunks and freeze in wax paper. Once frozen I just throw all the pieces into a Tupperware container so I have chunk fish food when ever I want. Little ones up to say 5-8 cm are best and not too skittish. When they get to 13-15 cm size you need a huge tank which is well planted as they become VERY skittish and will dart around and jump out. I don't know if they are illegal in Michigan USA as I have not purchased any in probably 20 years and my wife FORBIDS me from having any more.
I have used this site for many months now to determine what type of fish I wanted and how to best care for them. One thing I did not learn that was very mportant was how piranhas adapt to other piranhas once they are set up in a tank. I had 2 piranha fry that I took care of and they are now at 7 cm. I wanted yet another piranha in my tank, so I went to the pet store and asked their advice. I was told that the new piranha may harm my other because it was 9 cm. I was also told that if this wasn't the case my other piranhas would attack the new one due to territorial reasons. Neither has been the case. I inserted the new fish, left ample chew toys in tank (feeder fish) and left the light on. I have found that piranhas are much more aggressive and active in the dark. So far there has been no problems. At first they would nip at each other a bit, but they are beginning to school together. I just thought someone who already had a piranha and might want more would like to know this. One last very important piece of info is to absolutely make sure that the tank is large enough to handle your piranhas. I would recommend at least 60-80 liters per fish.
Red belly piranhas are a very shy fish. They love beefheart and shrimp, and you should always have feeder fish in the tank so as to keep the nipping to a miniumn if you have more than one. They will always be a shy fish, no matter how big they get. I can tell you from first hand experience they are pretty aggressive towards other fish, but when it comes to them being in a home tank, they will try to stay away from you especially while you're cleaning the tank. But by all means keep an eye on them while you are doing tank maintenance! Try to feed them a variety, such as guppies, gold fish, shrimp and beefheart.
I have owed 5 Red Bellied Piranhas for 7 years now, let me tell you a little about them! I started out with seven 1 cm piranhas and a 10 cm pleco in a 200 liter tank with the water temperature at 27°C. I fed them frozen bloodworms, brine shrimp, multi cube and flake food three to four times a day till they were about 3 cm. Then all of sudden I only had 6 Piranhas, so I figured it was time to introduce some live food into there diet, so they wouldn't eat each other! I started feeding them gold fish once a month along with feeding them the other food, still three times a day! After about one year they were about 10 cm in size. I started to change their diet by now feeding them live worms (NOT SCENTED), frozen or fresh shrimp no tails, live goldfish, big pellet food about once to twice a day. After about two years they needed more space so I moved them to a 400 liter tank. By this time they were about 15 cm in size and the pleco was about 18 cm. Now I feed them everything from goldfish, worms, shrimp, a variety of fresh and frozen fish, the biggest pellet food for fish, a couple handfuls of really big flake food, pinky's (baby mice), live leaches, live crawfish, lobsters (ooh that is fun), grapes, peas, lettuce, green beans, algae wafers (I love the loud crack of those), any live fish, carrots, and oh yeah my hand if I'm not careful. I feed them about every four days, but the bigger the food the longer I wait, like for a lobster I usually wait a bout 14 to 21 days! After about four years I lost the biggest one in a move to a different house. He is now stuffed and on top of the tank! He was about 20 cm in size. Then the most amazing thing happened...I noticed thousands of little very very little Piranhas everywhere. I did a triple take and it took me a few seconds to figure out what had happened! It was very weird, they started mating every week or two for about six months, I had baby Piranhas coming out of my ears. Its been 7 years now and I have sold thousands of piranhas over the years and now they only mate a few times a year and they are about anywhere from 15 cm to about 23-25 cm in size. Oh, by the way, I have gone through 4 Plecos, each time getting a larger one. The one that is in there now is about 40 cm in length and he has been in there fore about 18 months now. These fish are my boys and I have loved every minute of it!
I have 3 red belly piranhas. I find them to be quite shy and they do not appreciate bright light. They love to hide amongst driftwood and amazon swordplants. I feed mine gold fish as a treat, but use nutrafin cichlid pellets as a staple diet. They love darting up to the surface to snag them or to catch them in the filter downcurrent. Very misunderstood as savages, they will usually shy away from a hand during tank maintenance. I have never been bitten since purchasing mine a year ago, but make sure they are well fed before invading their space. Purchase them as juveniles and they grow quickly and develop striking colours, and become quite the conversation piece. Just be sure that you're ready for the commitment of keeping a group of large fish for many years.
About a year ago I purchased 3 Red Bellied Piranhas. I just recently found out that they love earthworms. It's probably one of the least expensive and fun ways to feed these fish. Mine eat so many worms that they can't swim straight, because their bellies are so full. This is obviously one of their favorite kinds of food, try it out!
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