PETCO Hi-Range Thermometer for Reptiles and Amphibians PETCO Hi-Range Thermometer for Reptiles and Amphibians affixes to aquarium glass and measures from 40? – 120? F. This accurate and easy to read thermometer is an inexpensive yet essential part of any reptile or amphibian terrarium. To get the most accurate temperature range inside your terrarium place a PETCO Hi-Range Thermometer in the warmest part of your terrarium and a second in the coolest area of the habitat.