There are actually quite a few different articles online about raising channel cats in small holding tanks. 300 gallons can support almost one fish per gallon provided ammonia levels are kept in check. My levels have been fine and I only do water changes about twice a week now - I did more in the beginning but once I checked ammonia levels I backed off as I felt it was unnecessary to change so frequently. It has been a fun little summer project. Made some mistakes but will do it again each year. It’s my evening ritual now - sun setting - I walk over to the tank and feed my cats. I don’t have exact data on growth rates but if I had to guess I would say they’ve gone from “LMB snack size (3”)’ to about 6” or a bit larger for some of the real pigs. I suspect most of them are large enough to survive predation. I plan to release them sometime in the next two weeks or so. I ran a bio filter and additional aeration just to keep the water
moving. I also added a large mass of lily pads because I thought it might help with water clarity. And as it turned out about a week after adding the lily pads the water became gin clear and has been ever since. That could have been that my bio filter finally hit capacity with the good bacteria too - so I can’t say for sure it was the lily pads.

Thanks for the above input on mortality. I guess fish just expire sometimes. I probably over think things - just always curious what caused it.