had about 8 dozen minnows i been nursing since the last tourney, they have been in a 6 gal water cooler with a areator running, been breaking up the top layer of ice each day but i worked two days and let a day slip by and just checked on them and there froze solid, i figured it would be harder for it to freeze with the aerator keeping the water churning but i was wrong, it is cold out there, yall stay warm