Fish or Fishless Cycling?
Cycling a fish tank is the process of encouraging bacterial growth which feeds on the waste produced by your fish. This 'maturing' of the filter bacteria can be done with fish in the aquarium or before fish are introduced.
What is cycling?
The processing of waste products from your fish is done by bacteria which reside mainly in your filter. In a new tank there are none of these bacteria, and they will form naturally when wastes are present but there is a tightrope balance of production of wastes and bacterial growth. If we have too much waste and not enough bacterial growth, wastes will build up and the aquarium will start a downward spiral of water quality problems. Cycling is the process of growing these bacteria, either using ammonia made by fish to provide the food for the bacteria, or by adding ammonia before fish are put in the tank.