fish keep dying

Question
I have a 55 gal freshwater tank. I've had a variety of fish.. all have died. Can you help me? I realize this is not about Betta's, but I am tired of my fish dying. LFS tests my water and says all is good. Each 'set" of fish last around 3 months. Could this be a cycling problem?

Answer
Beth,

 Yes there is a very good chance it is a cycling problem and very likely a water problem. If you are buying your fish from the same store the fish could be coming to you sick. If you have another fish store where you live, try buying fish from them. Make sure that you have a liquid water tester so that you can test your own water. Some of the stores use the test strips and they are not reliable. Sometimes they don't check to make sure the testing liquid expired. As long as your water is testing with no ammonia or nitrites and no more than 20 in nitrates then is has to be a fish problem. I hope this helps. If you have any more questions don't hesitate to ask.