What is the ratio of floaters to those that 'disappear'? If Texas ponds have thousands of TP, do you see thousands of floaters? Do maybe only 5% die and become visible on top? What happens to the rest? that seems like a big biomass to have thousands sink to the bottom and rot there?

The 2 years I had tilapia I would say I had maybe 5% or less that were struggling near the top and/or floating dead. I know we presume raccoons, herons, birds of prey get them but that wasn't visible at my pond either. Maybe the few turtles I had grab them from underneath and pull them down? the JAWS of the pond?