Traditionally, there are two ways to cycle a fish tank. Both methods will involve introducing ammonia into the tank which will be the food the bacteria need to survive. The most common method of cycling an aquarium is to use small community fish that produce the ammonia themselves. A kinder, more acceptable way to cycle a fish tank is to use a method called the "fishless" cycle. This also involves adding ammonia to the aquarium, but as a name suggests you do not use live fish. In this article, we are going to use fish as it's probably easier for a beginner to undertake, and we wouldn't be happy with youngsters handling pure ammonia as it can be dangerous. If you would prefer not to use live fish then read this article on how to carry out a fishless cycle.
You should cycle your fish tank with a small number of fish. Theyshould be hearty fish and a variety of fish that you want to have inyour fish tank in the long run. Do not cycle your tank withlots of . Do not cycleyour tank with any goldfish unless you intend to keepgoldfish. Unfortunately many pet shops still suggestthis. If you want to know why, you could review my .
To cycle a fish tank basically means to establish, cultivate or grow a bacteria colony inside your filter. As complicated as it may sound, it really is as simple as waiting for bacteria to grow. Just think if you were to leave your toilet uncleaned for several weeks, imagine how much bacteria there would be inside the pan. Cycling a fish tank is basically the same process because you are relying on the toilet habits of your fish to encourage bacteria to grow in the media inside your filters. Unlike the lavatory in your house where you really don't want lots of horrible bacteria present, you are relying on all the bacteria inside your filter to actually keep your water clean and your fish alive.
The reason is because the type of bacteria that are found naturally in a cycled fish tank are sensitive. They do not have an indefinite shelf life, and must be kept out of temperature extremes.