With water temperature being such a critical factor for the well-being of fish, it?s important to have a good thermometer. This Marina Plastic Thermometer comes with a suction cup for easy and reliable installation on your aquarium glass. Accurate and easy to read, it provides temperature readings in Centigrade and Fahrenheit. It also has a safety zone temperature range indicator for most tropical fish. For fresh or saltwater aquariums. Other thermometers available : 11200 Marina Floating Thermometer, Centigrade-Fahrenheit 11201 Marina Floating Thermometer with suction cup,Centigrade-Fahrenheit 11202 Marina Standing Thermometer,Centigrade-Fahrenheit 11203 Marina Stainless Steel Thermometer,Centigrade-Fahrenheit 11204 Marina Large Floating Thermometer with suction cup, Centigrade-Fahrenheit,