I just set up my new 25 gallon tank and had a simliar problem. I didn't cycle the tank or do anything like that. I put in the water, used stress-coat and stress-zyme, then the next day(~28 hours later) put in 6 guppies, 2 green corys, 1 bristlenose pleco, 3 upside-down catfish, and 10 neon...