the temps in my aquaponic system got to a low of 47f last winter, and i lost a few tilapia.. i turned a heater on to keep the water in the mid 50's and had no problems.. water hit the 60's and they started feeding really well..
i don't think you'll find any that will overwinter in an ohio pond..
Blue's are (from what i've read) the most cold tolerant, i have niles and blues, the fish i lost when it got cold were a few niles and one blue..and i have quite a few more niles than blues..
the breeder i got my niles from is in northeast ohio, blues came from Rex
i harvested 15 fish a couple weeks ago, they were 1" in july '12, over 2lbs at harvest..(10lbs of fillets from 15 fish)
