Dying Fish

[jerryacroley]

I have a 55 gallon aquarium with the standard hood and 18 inch lights, with a large filter system emperor, I think, and two large air pumps pumping through air stones. I have a heater set on 70 degrees for goldfish. This was previously set up for freshwater tropical fish, tank has been established for more than a year. I have recently put 6 two inch goldfish in tank and they all died in less than two hours. They looked like they were struggling to breath. I had the water tested yesterday, the person at fish store said water was perfect. 6.8 ph, no ammonia or nitrates or nitrites, the only suggestion she gave me was somehow the oxygen has been depleted or else some kind of poison substance has gotten in water, which i don't think has happened with a full hood being over tank. I am really at a loss, can anyone help me.
Thanks in advance,
Jerry

[oscarbartoni]

With goldfish you should not need a heater. But one thing that you might want to concider is that the heater might be electocuting the fishes. There is a possibility that electricity might be leaking from the heater and causing the death of the fishes. The other thing that might be the cause is too much of a difference between the water that they were in and the tank water. How did you introduce thrm into the tank? How did you clean the glass in the tank and how did you clean the inside of the tank before you set it up for the goldfish? We want to answer your questions but you have to answer ours so that you can get your answers. What is the water chemistry that the live fish store told you that you have? Did you just start the filter before you put the fish in? Or did you put new cartridges in? How large were the goldfish and how long did they stay in the bag before you put them in the tank? Some pet shops have a live garantee of a day or more so you might be able to get new fish if you can find out what went wrong with your other fish.

[imported_beer]

Hey, I am sorry about your fish. It is horrible when you have your tank all set up for new arrivals and they die. One is bad enough, but losing all your fish must have sucked. My condolences.

Now for your fish. If they were gasping for air, I believe there was serious stress happening. I'd ask the following questions, in addition to those by oscar bartoni.

1. What happened to the tropical fish that were housed in that tank before? My friend was appalled by why his fish kept dying until he discovered an ex girlfriend had added a few dollops of clorox to his tank. Even replacements kept dying. Not to suggest the woman in your life are quite as nasty, but even chemicals accidently introduced ages back could still be festering in the water

2. Has the tank been cleaned before the new fish were introduced? How was it cleaned? Did you cycle if it was cleaned?

3. Did you introduce soap or bleach residue when you introduced the fish. Something as simple as not rinsing your hands well before you dipped it in the tank...not a likely *killer* but just a means of identifying how things can get into the tank.

I would agree with the retailer. If your tank parameters were low in nitrates and ammonia, and was cycled, and if your filters and aerators were working fine, accidental introduction of chemicals seems the most likely culprit. Electricity is likely, but if you didn't get a jolt while introducing your fish to the tank, it is not very likely, possible but not likely. If I were you, I'd do a complete change and cycling before I introduced more fish.