For today's modern fish keeper there are a range of aquarium thermometers available. Which one you choose will be decided on your personal preferance as all do an adequate job of monitoring temperature.
Stick On Thermometers
Stick on aquarium thermometer attach to the outside of the aquarium to provide a constant temperature reading. The temperature sensitive crystals used will change colour to indicate the current water temperature. Contrasting colours allow for easy reading. The temperature is highlighted by the active crystals which correspond to the numbers printed on the thermometer face. Most Display aquarium temperature in both metric and imperial scales.
Digital Aquarium Thermometers
Digitial thermometers with an LCD display are attached to the aquarium by means of a suction cup or clip. They either sit inside the fishtank or on top of the tank in which case probed must be placed in the water. Digital thermometers are almost always sold complete with a battery which should last many years.
Thermometer Cleaning Magnets
Recently cleaning magnet manufacturers have begun to incorporate a thermometer in their products. Such products are often left in the aquarium where the thermometer can keep a constant check on the water temperature. Dual purpose aquarium accessories such as this one are both novel and practical.
Glass Aquarium Thermometers
For traditionalists their are still glass thermometers available. They work on the expansion and contraction of a liquid to guage the water temperature. They are sold complete with suction cups to attach them inside the aquarium.
Hand Held Aquarium Thermometers
If you have a lot of aquariums you may consider a hand help thermometer. Electronic models give a fast reading on the LCD panel. The stainless steel probe can and should be sterilised in between it's use in different aquariums.
Aquarium Thermometers For Sale
Below are the aquarium thermometers currently at auction on eBay. Also see the full range of aquarium thermometers available from eBay stores.
Aquarium Temperature Related Reading
Aquarium Chiller | Aquarium Heater | Aquarium Temperature