RB Piranha comp.   - 04/20/07
Hi Bob,
<Well, it's actually Neale, but Hi anyway!>
My son purchased some red bellied piranhas (Babies).
<I trust he bought a book about piranhas first? These are neither easy fish nor ideal fish for beginners. They are also rather large and basically boring pets. Great for people with space and experience, but terrible for children.>
However two smaller ones keep attacking the larger one.
<Absolutely normal. As any book about piranhas will tell you, these are intensely hierarchical schooling fish that live in swarms of hundreds of specimens. When kept in twos and threes their normal behaviour is short-circuited and the dominant fish *invariably* ends up bullying the one at the bottom of the social order. This is repeated as each fish below the "boss" dies, until you have a single specimen. Being schooling fish, they are very unhappy kept alone, and this singleton is nervous, flighty, and not at all entertaining.>
First time they ate his fins, tail and took out an eye (hence his name eyeball). I got a divider so that eyeball could recover which he did. Today however, the two smaller ones again attacked eyeball eating his fins and tail. Eyeball can not stay in an up right position, so again I put in the divider and have eyeball suspended in a net in an up right position. I have kept him alive now for 11 hrs, but was wondering how long I should keep him in the net?
<Well, piranhas heal very quickly when in good condition. They have to: their mating rituals (if you can call them that) involve biting chunks out of each other. But as should be glaringly obvious, there's no way that "Eyeball" can ever be kept in the same tank as the other two specimens. Oh, and it's probably a matter of time before they fight. So be sure and get three large aquaria set up, one for each piranha.>
Should I keep him there till I see signs of re growth of his tail?
<Yes. And also when the wounds are nicely healed. And I'd keep treating the water with something anti-microbial, such as Melafix.>
I feed them plenty (shrimp, fillets, snails, krill etc...) just do not understand why they attack eyeball.
<As said above: from being kept in appropriate numbers. They are doing what comes natural.>
All the fish are healthy otherwise.. At this point I do not want eyeball to pass away (so much work has gone into keeping him alive) water conditions are right on target.. Not sure if keeping him in a net in the up right position is the best idea, but at least he is not laying on his side on the bottom of the tank. Any suggestions on how I can help him heal quicker so he is not confined in the net but is still up right?
<Sounds to me you're doing the right things in terms of triage. But keeping him in a hospital tank is probably the best route, and actually inevitable really because this fish will have to be kept apart from the other for the rest of its life.>
Thank you so very much for having a wonderful site for people to use as a reference.
<No problems. Glad to help. Now please, sit down with your son and discuss the future. A "safe" number of specimens is 4 in a 75 gallon tank. You can keep more than that, adding around 20 gallons per specimen. If this isn't on the cards, then your son may need to think about re-homing these fish. If he wants something piranha-like, Exodon paradoxus is easy enough to obtain, but smaller, and just as fierce; it's also prettier and more active, and will even eat flake. Finally, please make sure he isn't using live feeder fish for food. That's a sure fire way to introduce parasites and pathogens. Goldfish and minnows also have serious nutrition problems because they contain thiaminase. The only safe feeder fish are livebearers bred at home. But with piranha you don't even need those, and your fish will be healthier given a pellet/stick staple diet carefully balanced to have all the nutrition fish need. Augment periodically with "treats" such as frozen silversides and lancefish. There are plenty of good books about piranha, and as a good mother it's up to you to teach your son about research and responsibility. Too many young boys buy piranhas because they are "scary" and then suddenly discover that, like all animals, they have needs and must be cared for properly.>
Dar

My new tank, poor FW mix of lvstk., ich   1/31/08
hi,
Currently I have 55G tank which contains four 2inch gold fish , six 2inch koi carp , two 4inch koi carp , six 2inch angels and one 25cm Pleco. I know it's a small tank ,that's why I am building a new 200G tank.
<Very good.>
I am thinking about buying 2 red bellied piranha. Is that a good idea?.
<To mix with these fish? Absolutely not. In addition, most of the common piranhas in the trade, including Pygocentrus nattereri (the Red-bellied Piranha), are essentially solitary fish in aquaria. Their social behaviour in the wild is extremely complex and difficult to replicate in captivity. Juveniles may school together, but adults only form schools under certain conditions, and when mature the males are territorial and ultimately guard nests and eggs. Unless kept in BIG aquaria where there are AT LEAST SIX specimens, piranhas simply don't work in groups. The dominant male systematically harasses and eventually kills the other fish. The flip side to this is that single piranhas are nervous and scared of their own shadows! They are very VERY boring pets.>
Is there any kind of fish that I can add with the piranha's?
<None.>
Right now I have one more problem , one of my koi carp is scratching ,what should I do .
<Likely Whitespot/Ick and should be treated accordingly.>
Is it necessary to remove live plants before adding any medicine into the system?.
<Not normally, no.>
One of my koi carp has full red body with small white patches in the middle, is that what u call white spot disease.
<Sounds like it.>
And last I want u to suggest a suitable filter for my new 200G tank (please mention the company name also)
<The ideal filter will vary. If the tank contains just fish and no plants (or maybe floating plants or plants attached to wood) then an undergravel filter can work very well. Use at least two powerheads to get a gravel bed this size working properly. Alternatively, you can use one or more external canister filters. These work better with tanks that contain plants. In either case, the brand of filter doesn't matter much, though some brands, notably Eheim, have a good reputation for reliability and value over the long term. The main thing is turnover. For large fish like yours, you want the powerheads or filter pumps to produce at least 6 times the volume of the tank in turnover per hour. So in your case, the pumps should add up to 6 x 200 = 1200 gallons per hour.>
thanks a lot Mathew
<Cheers, Neale.>