asap please

Question
We have over 50 pirahnas and we put them in a bucket until we clean the tank and when put them back in the tank they went right to the bottom of the tank.  And a few died, I have an over 50 gallon tank. please help!

Answer
Well, to start I would say there are way too many fish in your tank even though its a 50 gallon. Especially since they are pirahnas, while they do school as fish they are way too over crowded in the tank. Depending on how big they are, you would have to have at least a 100 gallon tank to aqequately give the fish space. As for the sudden death, I would imagine it is from stress. While pirahnas are active and viscious fish, they are easily stressed. Most fish go to the bottom when they are introduced to a new tank, it just means they are stressed. Those who died probably could not handle the stress. Also, perhaps the stronger ones saw the weaker ones struggle and decided to eliminate them from the school to prevent a weak school. Even if the dead fish were not eaten the ones still alive could have pestered the fish to death. Finally, unless there are signs of diseases or parasites on the fish to most likely cause of death is stress. Unless they twitch, rub on rocks or plants, have white salt-like spots, have a film on the body of fins, have what looks like eaten fins with a white film on the fins, or are showing other signs of disease or parasites, chances are they have been extremely stressed and some if not most could just not handle it. In the future I would advice investing in tools which let you clean the tank without putting your hands in also which alow you to leave the fish in the tank. With such tools you can reduce the stress on the fish. You could also get a tank seperator and put the fish in one half on the tank while you clean the other and vice versa. There are ways to clean a tank with pirahnas without danger to you and it reduces the stress on the fish to leave them where they were to begin with. Let me know if you notice anything else or if you have more questions.
                                         Rachel A.