JJMG Fish Tank Thermometer. This thermometer as a temperature range of approximately 10°F to 140° F, and is ideal for keeping the temperature in your tank … Reviews also suggest that it’s a very accurate thermometer. Best Dual Temperature Readings – Zoo Med Digital Aquarium Thermometer The Zoo Med Digital Aquarium Thermometer is made for tanks of all sizes, and it is easy to use. This Thermometer has a minimalist design that could make it almost blend with the aquarium, depending on the tank’s design. Operating the device is simple too. This fish tank thermometer has been reported by buyers as easy to mount and does its job well. Some users felt that the size was bigger than expected, but then it allows for easier reading. The product goes on the outside of the aquarium, and it measures the temperature … This removes the need for wires, making your fish tank look less messy. $16.99 #6. The large digital display on the UPLY Digital Aquarium Thermometer is easy to read due to the large numbers. The thermometer is submerged in the water because it has a built-in sensor. Buy Now from Amazon. Aquarium Thermometer, Digital Touch Screen Fish Tank Thermometer With Large LCD Display, Stick-on Tank Temperature Sensor Ensures Accurate Reading for Aquarium Terrarium Amphibians and Reptiles… 4.5 out of 5 stars 1,479.