FYI there are at least 2 different temp issues. One is lower lethal temp for the species and the second is the rate of change. One is fatal and the second is also often fatal. Example - assume tilapia lower lethal temp is 55 - if water is 54 the fish will die but if the water is 60 and you stock from 70 stock water the rate of change will likely also kill them.

In addition if water is cool but above lower lethal and fish survive stocking but water stays cool (lets just say 60) for 2-3 weeks there will be little growth or feeding due to suppressed body function in cool water (metabolism of cold blooded fish is suppressed).