A majority of the aquarist must rely on
different types of heating devices to ensure that the aquarium water
temperature stay high enough. This is especially true for those keeping
tropical fish species, since such species can require a water temperature of
27C (80F) or higher to do well. If the temperature drops too low, the
metabolism of your fish will suffer and your fish will become less and less
active. Low temperatures will also make your fish more susceptible to
illness and even small temperature variations can kill a fish. Some types of
more adaptable fish will try to hibernate when the water becomes too cold,
but sleeping fish is not very fun to watch in the long run. In some parts of
the world aquarists are forced to install coolers instead, to make sure that
their cold water species do not get too warm in the aquarium during hot
summer days.
You should always research the
particular species that you are keeping or planning to keep to find out what
their preferred temperature is. Some species will survive even in colder
water, but they will not do well and they might for instance refrain from
spawning.
A commonly used rule of thumb states
that you will need roughly five watts of power to heat one gallon of water
or 1-2 watt per litre. A 20 gallon tank will consequently require a 100 watt
heater, an 180 litre tank could do with a 200 or 250 watt heater. If you are
in doubt you should pick the lower amount of watt since you don't want to
risk cooking your fish. When you buy fish tank heaters you can usually
choose between pre-set heaters and heaters that you must set your self. The
more convenient types of fish tank heating will contain a thermostat. If you
buy fish tank heating without a thermostat you must buy a separate
thermostat and install it in the aquarium.
We recommend keeping a spare heaterstat
at all times. Many aquarists will have heard those horror stories of failing
heaters killing all their fish when they were a weekend away. It's a small
additional investment which could save lives!
