Over the past few days I have lost 6 fish, I can't figure out what is going on. I have no amonia, no nitrites, and my nitrates are under 20, my
pH is neutral and my temp is a steady 80 degrees. I have a commutily, heavily planted, 55 gallon with assorted gouramis, polka dotted cats, otos, upside downs, corys, etc. I had a batch of gouramis that died rather quick a few months ago, that were very skinny and there eyes were sunk in, but no problems since. The 2 polka dotted cats that died were among the oldest fish in the tank, I can't belive they are dying, the last one looked like he wasn't going to make it as of this morning. All the other fish seem happy until they drop dead. What the **** could be going on? I've already done two massive water changes. Please help.