Are you getting started with your first fish tank? Then you may have heard of something called the “aquarium nitrogen cycle,” followed by a bunch of complicated scientific terms and graphs that seem a little overwhelming. No need to panic! Keep reading as we explain the nitrogen cycle in this very short and simple guide.
The nitrogen cycle basically describes how nature creates food (in the form of microorganisms and plants), fish eat the food and produce waste, and then nature breaks down the fish waste so that it can get converted into food again.
When aquarium hobbyists talk about the nitrogen cycle, they are usually referring to the specific part of the cycle where the fish waste turns into toxic nitrogen compounds like ammonia, nitrites, and nitrates. These nitrogen compounds can potentially kill our fish unless we make sure we have plenty of microorganisms (also known as beneficial bacteria) and plants to consume the waste products.
For the purposes of our illustration, let’s use yellow, brown, and blue M&M’s to represent the three toxic nitrogen compounds:
Yellow = ammonia (which is very toxic and can burn fish gills and skin)
Brown = nitrite (which is somewhat toxic)
Blue = nitrate (which is not as toxic as ammonia and nitrite)
“Cycling your aquarium” simply refers to the process of making sure you have enough biological filtration (e.g., beneficial bacteria and aquarium plants) so that all the ammonia and nitrites get eaten up right away. If you have an aquarium water test kit, ideally you should measure 0 ppm ammonia, 0 ppm nitrites, and usually some amount of nitrates in your tank water. If the nitrates reach 40 ppm or more, then you need to remove some of the dirty tank water and replace it with fresh, clean water.
Use a water test kit to measure the toxic nitrogen compounds in your aquarium and determine whether or not you have enough biological filtration.
This naturally leads us to ask how to we make sure there’s enough biological filtration in the aquarium to handle toxic nitrogen compounds. One easy way is to of course add more aquatic plant, which will happily consume the ammonia and nitrates produced by your fish’s waste. Just remember that if you don’t have enough fish waste to feed your plants, they could starve to death, so you’ll need to supplement with a good, all-in-one fertilizer like Easy Green.
If your plants are not thriving, consider using an all-in-one liquid fertilizer to make sure they have all the nutrients needed for healthy growth.
As for growing beneficial bacteria, there is a common misconception that buying bigger or more filters will increase the amount of bacteria in your aquarium. The truth is that beneficial bacteria grows not only in filters but also on every surface in your aquarium, such as the gravel, glass walls, and decorations. Buying more filtration simply means you have greater capacity to hold more beneficial bacteria, but if you only have a few fish, your decor alone may have enough surface area to colonize the necessary beneficial bacteria.