“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. (The aquarium plants consume the nitrates to produce new leaves.) You must remove the nitrates either by doing a water change or by using aquarium plants.

Step 5: Eventually, the amount of nitrates will build up and can become harmful to the fish in high amounts. Step 4: The fish continue to eat food and produce waste, which gets processed from ammonia and nitrites into more nitrates. Step 3: Beneficial bacteria #2 then eats the nitrites and produces nitrates (the least toxic nitrogen compound). Step 2: Beneficial bacteria #1 eats the ammonia and produces nitrites. Step 1: Whenever your fish goes to the bathroom, some ammonia is produced. Blue = nitr ate (which is not as toxic as ammonia and nitrite).Brown = nitr ite (which is somewhat toxic).Yellow = ammonia (which is very toxic and can burn fish gills and skin).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.įor the purposes of our illustration, let’s use yellow, brown, and blue M&M’s to represent the three toxic nitrogen compounds: 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. 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.Ī simplified diagram of the nitrogen cycle in aquariums What is the Nitrogen Cycle for Aquariums? No need to panic! Keep reading as we explain the nitrogen cycle in this very short and simple guide. 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.

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