Instructions
Choose a tank appropriate for the number of adult fish. A crowded environment not optimal for a pond works to hinder territorial behavior in aggressive male fish. A 50-gallon tank should hold no fewer than three and no more than 12 adult fish.
Purchase a submersion heater appropriate for the size of aquarium. Models are available with or without temperature gauges. Though more expensive, internal gauges simplify initial setup but still require verification with an external thermometer.
Set the heater in the tank. Refer to the manufacturer's instructions for the tank position recommended for your model.
Leave the tank alone for at least half an hour, then check the standing temperature with an external thermometer. The sitting period allows the temperature to equalize.
Plug in the heater and check the indicator light. A small red or orange light should come on to show that the unit is currently operating and heating the water. If the heater is on, turn the thermostat slowly until the light just clicks off.
Heat the water by carefully turning the thermostat until the light clicks on. Let the heater operate for half an hour, then check the temperature again. Repeat until the desired temperature is reached.
Cool the water by waiting until the indicator light turns on by itself. Carefully adjust the thermostat down until the light clicks off. Check the tank after half an hour, and repeat until desired temperature is reached.
How to Heat Tilapia Tanks
Tilapia continues to grow in popularity, not just at the supermarket and restaurants, but also in catalogs targeting backyard breeders interested in this sustainable source of protein. Temperature tolerances vary by breed, but most tilapia prefer water kept at 77 to 86 degrees, with hardier stocks tolerating overnight drops as low as 47 degrees. In warmer climates, fish can be grown in ponds outside, but during the winter, or in colder areas, tilapia require insulated, heated tanks.