1 Answer

The nitrogen cycle if,you are speaking in aquarium terms is this:

You set up your aquarium with gravel, water, decorations... maybe plants... the filter is going and then you add your fish.

You feed your fish.

The fish go to the bathroom.

The decomposition begins.

The nitrogen cycle is the measurement of the negative waste product against the amount of positive bacteria.

It takes nine days for the amonia and waste to promote the growth of positive bacteria.

Amonia and waste builds at a rate far more significant than the new and positive bacteria can possibly grow ... a measurement of negative and positive.

The entire cycle takes 6 weeks from start to finish.  The fish can live throught the cycle... you should never put them into the cycle once the ninth day has begun.

Fish will adapt to as long as you have chosen fish who can live through the cycle. (Stay away from live bearers)

9 days up... 21 days at the top and 9 days down.

Then you can add new fish.

Put the least amount of fish you can stand to look at for the first 6 weeks and slowly add some more after the cycle is over... Do not overpopulate your tank and never overfeed.

A fish's stomach and eyeballs are exactly the same size unless that fish does not have a rib cage... This rule does not apply to fish you would never keep in a tank.

After this cycle is over... When it has been set up for 3 months...change one third of the water every 3 to 4 weeks from the bottom of the tank like clockwork.

And please don't let anyone talk you into an undergravel filter no matter what.