PLEASE HELP I THINK MY PIRAHANAS ARE DYING :'(?

[shell]

DATE - 3rd Feb

ok so long story short i bought this tank with 2 red bellies in it, when i was speaking to the guy i thought he sounded like he knew what he was talking about and knew his stuff about tanks etc so anyway when i got the tank in the water just about covered the fish so i proceeded to fill it to just over the filter like he said and both fish were hiding which i figured was from shock/fear etc from being moved and having hardly any water for however long anyway this morning i was watching them for a bit as u do lol and both fish have found a place each in the tank and are just sat on the bottom doing that opening and closing mouth thing like gasping like fish tend to do with lack of oxygen at the top of the water (if that makes sense) and i thought these fish really dont look too great so joined a cpl of fish groups on facebook to see if anyone could give me any advice and thats where i see the same person asking about other types of fish coz he is getting a new set up with sharks or something and someone said about cycling his new tank and he didnt have a clue what they meant.... so thats my first Question....... Do you need to do the cycling process for pirahanas??

he also said there is no way he would have an empty tank for the length of time it takes to cycle a tank properly which tells me that this tank defo hasnt been cycled. he gave me "a bag of food" which was some prawns from the supermarket, and thats when i thought this really isnt looking great......

on top of this, the filter that is in the tank is throwing water back out that powerfully that the fish cant swim about, there is no lid on a tank with fish that jump also no lights and there is 2 of them which i know isnt good as there should be a min of 3 otherwise one will eat the other - am i right so far please???

anyway i went to the pet shop and got proper food, some tap safe and i bought a new tank (71 litres/ 2ft) with filter, heater etc and he even gave me some of his media and tank water in a bag to hurry along cycling.

so my next Question is where do i go from here how can i get the fish into the new tank so they can get better?? or what do u recommend i do now to stop these 2 fish from dying please,?

should i use the carbon out the old filter in the new filter with the new carbon to speed up the cycling process, im so confused ?

also i know i cant buy one new pirahana to make the numbers odd but what would happen if i was to buy 3 more would they be ok? or if i was to get one that wasnt still a baby as one of these is about 4 inch and one about 2 inch that we have already sorry for the length of my question thankyou

Thankyou in advance any help is appreciated asap pls

[Richard]

this is what i would do if i was you,,your water is very important needs to be P.H.level 7,,,,then get a long air stone with a pump,the more air in your tank. and get all you fish the same size the better the fish will be,and the best outside or underground filter you can get,,,,why all this,,,,because pirahana,are a pig fish like oscars .they will eat any thing you put in,,, for them..good luck and trout pellets and feeders are the best food...P.S if you put them in a 55 gallon i had a pair grow to 5 lb. a piece.......

[Aaron]

It does sound as though the original tank wasn't cycled. Using the used media will help, but the water you got won't add anything beneficial - bacteria attach to the surfaces in the filter and tank, they're not free-floating). What you can do while the filter is cycling is to use a bacterial supplement (Stability by SeaChem is a good one, there are other brands as well) to jump-start the bacterial colony in the tank. Monitor ammonia and nitrite levels to know when water changes are needed until the tank is finished cycling.

The number you should keep in a tank is debatable. Some species are definitely loners, and some people who keep them think fewer is better, even among those that normally school. If you get more, you should get ones preferably around the size of the ones you already have if you intend to keep them, and can provide the correct conditions (more on this later). Pirahnas are just a large, aggressive type of tetra (really!) and some species have the same schooling behavior and social structure. So they should be kept in a group of at least 5 if you do want a school. But when you consider that each one will get to around 1 foot (30 cm), a 71 liter tank isn't practical for housing them for very long. A fellow fish club member of mine breeds these, and uses a 125 gallon (473 liters) to house the adults and you probably shouldn't try to keep them unless you're willing to provide at least a 75-90 gallon (283-340 liter) tank.

The filter sounds like it's too powerful for the tank it's in. Most have a way of adjusting the flow, though. See if the flow can be reduced, and if not, position it at one end of the tank so it flows towards the other side across the short distance across the tank. The flow will hit the opposite wall, and the current will be spread out across the rest of the tank giving the fish a sheltered area off to the opposite side in the long direction across the tank. You can also use a clean plastic bottle to make a baffle to slow down the current http://www.bettafish.com/showthread.php?t=30139

If after reading this, you decide to get more pirahna, you want to add at least 3 of them. This way, when the established fish pick on the newer ones, there will be several so any agression is spread out. Be sure to have plenty of cover (plants, rocks, driftwood) so the new fish have a place where they can duck into to hide. If your tank allows, you could use a divider at first, so the fish can see and smell each other without making physical contact, and letting the newcomers at least become familiar with where they can hide on their side of the barrier. Or, rearrange all the decor in the tank to put all the fish on equal footing, so there aren't any established "territories" and all the fish will have to get used to the new layout. And try to get ones that are similar in size, pirahnas will eat other pirahnas. If you decide that adding more of these fish and getting the size of aquarium they will need is more than you want to do, see if you can take the fish in to your pet store and trade them for something more appropriate for your 71 liter tank.