Heaters are an essential part of keeping your fish tank at the right temperature for your fish. Heaters come in a variety of shapes and sizes, from small to large, and can be used to heat both freshwater and saltwater aquariums. They can be used to maintain a consistent temperature, or to raise the temperature of an aquarium during the colder months. Some heaters also come with thermostats to help you monitor and adjust the temperature of your tank. With a wide range of options available, you can find the perfect heater for your aquarium.