With water temperature being such a critical factor for the well-being of fish, a good thermometer is a must. Marina glass thermometer is the perfect device that helps you monitor the temperature of your aquarium. It is designed to float in the water in a vertical position. It comes with a suction cup for optional installation on your aquarium glass. Accurate and easy to read, it provides temperature readings in Centigrade and Fahrenheit. It has a safety zone temperature range indicator for most tropical fish. Suitable for fresh or saltwater aquariums.