The only fish to ever survive until tilapia, were the Green Sunfish and I know why. I have determined Green Sunfish do not require oxygen.(Slight exaggeration) Last year we trained the Tilapia on whole kernel corn by throwing a few handfuls a day out during the year. By fall you could literally catch a fish a second, no exaggeration.
Early on, we would catch 10 to 1 Green sunfish. By October, reverse those numbers. The wild thing a found out about Green Sunfish is I would take a couple of buckets to hold the fish we caught. Tilapia would pipe to the surface fairly fast, However, I noticed you could cram dozens of Greenies in a bucket and the never acted like they were stressed.
The years we had horrible watermeal and duckweed problems, Green Sunfish survived by the thousands.
Last year I started letting all the <2 lb. LMB from the big pond go in the small ponds. Caught a few in the fall that looked like they swallowed a basketball. Those middle ponds are muck filled nightmares. Last year I was putting in some floating islands (Thanks Adirondack) and sank past my knees in muck. The pond was only 5 or 6 ft. deep originally and now with all the undecayed tree limbs and leaves more like 0-3 feet. Told the family we will need to dig it out someday, but I’m not holding my breath.
