How to choose an aquarium heater
-Look for affixing options. The last thing you want is for your heater to come loose and float around the tank, so ensure there's an affixing option such as a suction pad.
-Consider a display monitor. By choosing a heater with an LCD screen, you'll be able to track the temperatures inside your tank and make sure it doesn't get too hot or too cold.
-Invest in a guard. Aquarium heaters are perfectly safe, but in very rare cases can lead to your fish getting burned if they swim too close to the heat source. A guard can prevent this, and also protect your heater from damage.