you will need a higher-watt heater. Place one thermometer inside the tank and one outside to maintain the best temperature. Immersible or submersible: An immersible heater lies above the aquarium ...

Details: This recall involves all 50-, 100-, 150-, 200- and 250-watt Top Fin brand plastic aquarium heaters. The heaters are black cylinders about 1 1/2 inches in diameter and about 13 inches ...