I have a 45 gallon tank which has been cycled, but I currently only have one fish, a sunset gourami. I'm having trouble keeping fish alive. I was going to post a detailed description of what I've been doing on one of the other forums to see if I could get advice. My levels are all fine and I do 20% water changes every 2-3 weeks, but I've lost 9 fish so far over the past few months. I've switched where I buy the fish from to see if that was the issue, but it was not. Unfortunately, I think I may know the problem, but not sure how or if there is a fix for it. I had a nitrate/nitrite spike which I believe I caused by overfeeding. Around that same time our well pump broke so I couldn't do an immediate water change. The guy who fixed the well pump put about a 1/4 cup of Dawn dish soap down our well because it kills some kind of bacteria. I wasn't there when it happened to object because I know soap residue is lethal to fish. For several days soapy water came out of our faucets so I waited to do a water change. When I finally felt there was no longer soap coming from the faucet I returned to my normal water change schedule, but I've had trouble keeping fish alive ever since.
to AA! 
