Product Price Accuracy (°C) Resolution (°C) Display Type Waterproof Level Size (mm) Battery Life (hours)
AikTryee Aquarium Thermometer, Fish Tank Thermometer, Water Thermometer seachem Prime with 3.3ft Cord Fahrenheit/Celsius for Vehicle Reptile Terrarium Fish Tank Refrigerator
US
£22.71 ±1 UHD LCD 2.28*1.4*0.47 in up to 8 months

This is an AikTryee digital aquarium water thermometer with a wired probe and dual Fahrenheit/Celsius display. It has an LCD screen and is designed for easy suction-cup mounting in aquariums or terrariums. The thermometer uses an LR44 button cell and is reported to work for up to 8 months.

★ Ideal for

It's designed for easy reading with a 1.6-inch LCD display (listed on a retailer page), making it a strong pick for the largest display among comparable options.

Aquarzon 3D Transparent Beautiful Slim LCD Aquarium Thermometer with Free Battery in Retail Box
US
£5.98 ± 0.0 to 1.0 degree C 0.1 degree C LCD 7cm length X 2cm height around 1 year

This is a slim, semi-transparent stick-on aquarium thermometer with a clear LCD that's designed to be easily readable from outside the glass. It comes with a pre-installed free battery that activates when you remove a sticker, and it's intended for mounting on the outer side of aquarium glass. It suits most aquariums where you want a neat, low-profile temperature display without wires.

★ Ideal for

For easy reading, it uses a clear LCD screen designed to be quickly visible from the front of the aquarium, while also being ultra slim and semi-transparent for minimal obstruction.