esshup: The feed was from one of the first two bags of 20 that I picked up at TSC. I put 2 bags at a time in a tote on the bank and scoop feed till it's gone and then I get 2 more. I noticed when I emptied the first 2 bags into the tote that the feed in one bag was grayer than the normal brown pellets but had seen some color variation before so I wasn't alarmed. The feed is on a pallet and double tarped so it hasn't gotten wet. I started feeding with that feed the day after I got it. I have sent an email to Contact Us on the Sportsman's Choice webpage asking them if they will analyze the feed. I still have the bags so they'll be able to see the age of the batch number. I'll post what they reply. Also wondering if maybe I should reach out to Tractor Supply and see if they'll pursue analysis. I've bagged up and frozen a couple of the dead fish so they can be necropsied in the event that some entity will take on the investigation.

FishinRod: I've fed normally since the die off hoping to see catfish return to feeding. I've fed the food that I now think is contaminated until day before yesterday when it occurred to me that the feed is the cause of the die off. The sunfish and other small fish feed as they normally do and I haven't seen any dead fish except for the large catfish.

Sunil: The count of large catfish that have floated to the top is now over 60. The probable count of large catfish before the die off was around 120 large CCs and 20 large blue catfish. I suspect now that the large catfish are all dead. I have not seen a single dead fish of any other species.

jpsdad: The 2 weeks prior to the rain were unseasonably low temps and so the pond water was relatively low when the rain hit. The catfish did not come to feed the day BEFORE the rain and so I'm now thinking that whatever killed them was not an effect of the rain. Your list of species most to least likely to succumb to low DO level rings true to me. As I mentioned, the sunfish are fine and feeding normally. I'll go ahead and set the bream trap and see what I catch. I don't have time to fish with rod and reel but the trap will usually catch some of each species in the pond within a half hour.