Cycle

[raeburter]

What is cycling

 

[The-Wolf]

cycling is where bacteria change ammonia(fish waste) to nitrItes and another bacteria changes the nitrItes to nitrAtes. the nitrAtes make plants grow and (some)fish eat plants making waste(ammonia) thus creating the cycle.
for more indepth info see http/www.fishforums.net/index.php?showtopic=73365

 

[Tokis-Phoenix]

Yep cycling is important and you must do it unless you want to be doing 100% water changes in your tank everyday- as far as stocking levels are concerned, say you have a 20gal tank and you want to do a cycle with fish. Even though you could easily fit 10 guppys in it, you could only put 2 in it while it is not cycled or still doing its cycle.
Personally i suggest you for a fishless cycle mainly because you don't put your fish's health at risk and also because it is quicker, there's lots of articles on you to go about a fishless cycle on the beginners section .
To do any cycle though you will need a filter, dechlorinator and water testing kits- without any of these you can't realy cycle your tank.