I have a small stream that runs through my property in Georgia, USA (temps here change seasonally from 30-90 degrees farenheit). I have dug a hole and built a dam, creating a pond which i intend to use to house a small group of channel catfish. It isnt very large, only about 4,500 gallons. I ran into a problem when attempting to stock it with fish. Since the stream water is cold (i dont have an exact temp, but about 45 degrees) the catfish slowed down substantially. I know this slow down is normal, but they wont even eat. I've looked for pond heaters, but i can only find "de icers" designed to create a small hole a in frozen pond. Could these deicers function to raise the core temperature of the pond, or will i have to do something else to raise the temperature, such as reduce water flow?