It's hard to say what happened. All we can do is speculate, based upon what we know about chainstore petshops and stress assocaited with taking fish home.

It certainly isn't a far-fetched inference that many chainstores have workers that have only cursory knowledge of how to take care of the fish and that they didn't have the best care before you bought the fish. So that could have been the proverbial, "straw that broke the camel's back".

....or... it might easily be your new setup. By new setup do you mean a new filter, with perfectly clean filter medium? Then it is highly likely that the filter and bacteria hasn't had time enough to go through the Nitrogen Cycle and the wasteproducts killed the fish. Is your tank cloudy? Do you have an Ammonia / Nitrite / Nitrate kit?

oh my...so we NEED a filter? We got a air bubble thingy that keeps the water moving, also we did not know until today that the water needed to be 72-75 degrees!! We are getting my SILs heater as of tonite (sigh we woke up to another dead fish...) so we will buy the rest of the supplies tomorrow.

The pump only provides oxygen, but a filter does that removes waste products, which is very important. I would also raise the temp to the 75-80 range.

Be sure to cycle the tank, and don't overcrowd.

When the filter is running and the temp is stable,add 1 or 2 small fish and let it go.Make sure that for the next month that you don't add anything else,and make sure that no food hits the bottom during this period.I would also suggest a different supplier for your livestock.As we in the trade say,you don't buy a fish from PetSmart.....you rescue it!Good luck!
John

Okay found out what my problem was. At first we thought it was the filter that was killing them (we always found them in the filter or stuck to it) But a nice lady told us that it isn't the filter (she is a guppy breeder and even fry don't get sucked in!!) It was our water. It hasn't cycled. So we have been "cycling" our 20 gallon tank for almost a week. the lady said it should be safe to add only one fish at a time. The first day (Saturday) we set up the 20 gal. filled it up, added the de-chlorinator, Water conditioner....then let it sit for about 1/2 hour, then we added the Bacteria starter, then "cycle" that we bought from Petland (not petsmart). We have decided to start off with one fish from wal-mart (that stock is from the nice lady we spoke to and she takes good care of her stock) then we will look into the local breeders or even buy from a fish store (the ones that only sell fish)

I would recommend buying an Ammonia/Nitrite/Nitrate test kit to tell you where you are in the cycle. Without one, syou have clarity of water and whether the fish are dying to tell you.

valentinerottie, did you get a filter? The water doesn't cause the cycle it's bacteria in the filter medium that converts fish waste to a non toxic state. It couldn't be caused by not cycled water either. It takes time for uneaten food and fish waste to turn to ammonia. It cant happen in a new tank in a day or two. The most likely cause would be a ph difference in you water to the stores [fish can adjust to ph shifts only over a long period of time]. Clorine in the water could also be a problem but dissapates out of the water within 24 hours.

Get an Aquaclear 20 filter and the tank has to cycle. You may lose a fish or 2 during the cycle process. I'm not going to get into the fishless cycle or not debate. Also get those test kits, the one's that use the test tube are more accurate. Read up on cycling a fishtank. Just google it!

Tom

Okay I bought the new filter...The old one kept getting stuck and heated up reaaly bad. We paid $50 for the new one but it's worth it! We got the Nitrite/Nitrate test kit and we test nearly everyday. We also test the ammonia every second day. No more dead fish woohoo. We bought two Dojo Loaches and a goldfish...We are thinking of giving the goldfish to my BFs nephews because we don't like it, its so......messy!! lol. We love our Dojos and when I was fixing the bubble thingy one of them came up to my arm and "whiskered" it..hehe.

A goldfish in a 5 gal tank is a no-no. What brand/model filter dod you buy? Keep in mind the ammo will go way up till the tank cycles then go down to zero.

My filter broke four months ago so the water in my 29 gallon tank hasn't been filtered in four months and the guppies are still alive and look healthy. I also haven't turned om my heater in over a year and the fish are still doing fine. I haven't even changed the water in several months and it doesn't even seem to make a difference. The population seems to have reached an equilibrium where for every fish that dies another takes its place so I always seem to have the same amount of fish (about 30). I have one plant that is over three years old that seems to be enough to take care of the water.

I got some prolific guppies that I'm thinking of giving away or selling off. They're beautiful - just producing too often!

californian, the danger in what your doing is that at some point your ammo level will peak or ph crash and you'll lose most or all of the fish. Then a 100% water change will be needed and the tank recycled. Mant tropicals are hardy enough to do ok at normal room tempeture [@70].

James...We have a 20 gallon tank set up right now...