Fish are ectotherms or poikilotherms which simply means they are cold blooded. As a cold blooded animal fish are dependant upon the aquarium water temperature to regulate their metabolism. If you are not keeping an aquarium within the correct temperature range a fish's health will suffer.
Generally tropical freshwater and reef marine aquariums are maintained at a particular range of temperature. It falls in the 22-30 degree Celsius range depending on the species kept and their origins. Below 22 degrees Celsius is the desired temperature for cold water fish.
Temperature is sometimes raised or lowered under certain conditions. Most fish require a drop or rise in temperature to initiate breeding. This action mimics a change in season which coaxes the fish into spawning. Temperature is sometimes also raised or lowered while treating an illness or using a particular
There are two devices designed for regulating the temperature of an aquarium. These are known as aquarium heaters and aquarium chillers. Generally only one of these devices will be required depending on weather the water needs to be kept above or below the room temperature.
Temperature can be monitored using an immersed
or stick on
thermometer. Either will be accurate enough to monitor the fish's environment. Digital thermometers with alarms are also available for aquariums that require accuracy and safety.
During a prolonged power failure your fish may become at risk of leaving the optimum temperature range. In such situations it is convenient to keep pieces of polystyrene sheeting that can be taped on the outside of the aquarium until the power returns. Such insulation should cover the top of the aquarium while allowing some air flow onto the water surface.