Floating thermometer is a great choice for all the aquarium hobbyists and it provides you an actual result of your aquarium temperature. Operating the device is simple too. All in all, if you are looking for an inexpensive thermometer for your betta tank that is an alternative to a floating aquarium thermometer, the SunGrow Digital Betta Thermometer … You attach it horizontally by using the adhesive. 4.3 out of 5 stars 178. The thermometer … If you’re not a fan of suction cups, you’ll be glad to know that this thermometer can function just as well by floating … Buy Now from Amazon. The back of the thermometer senses the temperature inside the aquarium … This thermometer measures 0.75" x 4.25" and weighs a puny 0.3 ounces. It’s designed to go outside the aquarium and below the waterline. This type of thermometer is very cheap and most of these thermometers are made of glass which makes them considerably more fragile than the other types of thermometers. The large digital display on the UPLY Digital Aquarium Thermometer is easy to read due to the large numbers. Reports of residue on the unit; Reports of broken units; Reports of inaccurate readings; Summary. Lomodo 4 Pack Floating Thermometer Aquarium Glass. Better accuracy than floating thermometers; Cons. Hofun Swimming Pool Thermometer, Cute Design，Swimming Pool Water Thermometer with String, Outdoor Floating Thermometer for Swimming Pool, Bath Water, Spas, Hot Tubs, Aquariums and Fish Ponds. What We Like About UPLY Digital Aquarium Thermometer. Marina Floating Thermometer … ... Best Seller in Aquarium Thermometers.