Aquarium Thermometers

Your Bettas need a fairly consistent water temperature, and the only way to be sure they are getting it is with a thermometer. Stick-on aquarium thermometers consist of a peel-and-stick plastic rectangle applied to the outside glass near a corner. Liquid crystal film between the layers of plastic lights up in different spots as the water temperature changes.

Glass or plastic aquarium thermometers filled with red alcohol come with suction cups or hangers to secure them inside the tank. You read the temperature as you do with an ordinary fever or weather thermometer. Place the thermometer where you can easily see it but where it won’t detract from the scene inside the tank.