The proper temperature for most marine aquarium fish is
between 72 & 78 degrees Fahrenheit, with 76 being "ideal."
These temperatures need to be stable, as any rapid fluctuation in water
temperature could kill your fish.
To accomplish these stable
temperatures use the following tips:
Check the temperature of your water daily using an
aquarium thermometer.
Top Fin Floating Aquarium Thermometer Helps you maintain the proper temperature for your fish.
Floats in the tank or can be attached with a suction cup