Warning: Thermometer contains glass And small parts. The back of the thermometer senses the temperature inside the aquarium through the glass… 8 new TOP FIN floating glass thermometer. Directions: Instructions: Proper water temperature is essential To maintain the health And well-being Of your fish. … FIN 737257021600 Thermometer Specifications Shop all fish heating & lighting accessories online It’s designed to go outside the aquarium and below the waterline. Brand: TOP FIN, Type: Thermometer, UPC: 737257021600. FIN 737257021600 Thermometer Description. You attach it horizontally by using the adhesive. Top Fin® Floating Glass Aquarium Thermometer at PetSmart. JBJ Floating Glass Thermometer w/ Suction Cup for Aquarium Description Water temperature is a key factor in keeping tank inhabitants healthy. Keep out Of reach ofchildren. The JBJ floating glass thermometer sticks on the inside of … This thermometer measures 0.75" x 4.25" and weighs a puny 0.3 ounces.