The official definition for The Nitrogen Cycle is:
“The biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.”
Translating from nerd to English: the waste that a fish produces gets turned into another form and the good bacteria in your aquarium then breaks it down completing the Nitrogen Cycle and as result, creates a healthy eco-system that supports life.
Here’s how it works:
Step 1: Ammonia is produced by the fish’s waste.
Step 2: The ammonia then turns into Nitrite.
Step 3: Nitrite then turns into Nitrate.
Step 4: The established biological filtration system then breaks the Nitrate down.
So it basically looks like this:
A typical Nitrogen Cycle can take from 6 to 8 weeks to complete. Once your aquarium completes the Nitrogen Cycle, you will need to do regular water changes in order to remove excess Nitrates from your aquarium.