I found 1 catfish floating yesterday. I was hoping that would be the only one and my levels would start coming down. Today I found 2 more dead so I tested the water and levels were no better. I started a water change and found several more dead at the water intake and under rocks for a total of about 9 catfish and 1 goldfish. Hopefully the aggressive water change will help things bounce back. Very disappointing but hope the others will survive.