Well! What you need to understand about is 'Cycling'.
This is the process of preparing a tanks filter for biological breakdown of chemicals in the Nitrate cycle. A quick explanation of this:
Ammonia (Fish waste, wasted food, etc) is turned to Nitrite by bacteria in the filter. Nitrite is turned to Nitrate by bacteria in the filter. Nitrate is removed by performing partial water changes.
These bacteria take some time to grow, and this is where fish or fishless cycling methods have to be looked at.
By far the best way to prepare the filter is by fishless cycle, this means that you add pure ammonia to simulate fish waste and the bacteria grow in the filter feeding off of this. Its faster than cycling with fish, and it doesnt put any fish through stress and most likely fatal pollution.
If you can find any products that contain either 100% Ammonia or an Ammonia product that doesnt foam when shaken then you can do this! Look hard for Ammonia before you fall back on the less preferred method:
Fish cycling.
This means you put a few real fish in, preferably hardy fish like Zebra Danios (someone correct me if I am wrong on that choice) and let them swim in their own waste for a while until the filter starts to develop bacteria. Its harmful to the fish, but some people (myself included) have had to use this method.
The cycling process starts with Ammonia, and these levels will rise until the bacteria can break it down, at which point Ammonia will fall and Nitrites will rise. The Nitrites will eventually fall as the bacteria start to break that down also. When you have 0 of each, the cycle is complete and you can start adding fish.
There is a lot more you need to know, quick rundown is:
You need to treat water before it goes in the tank with dechlorinator, chlorines kill bacteria = bad.
You need test kits for the three chemicals mentioned. Some master packs come with all three, these ARE a necessity.
Take a look at the fish.orbust.net homepage, there is some useful info there
