The nitrogen cycle for beginners
If this had a second title, it would be “How Not to Kill Your Fish”. Please keep reading.
You may not hear about it at the pet store, but establishing the nitrogen cycle in your new aquarium is the most important step in successfully keeping your fish. Why? Because most living things produce toxic ammonia when they eat, grow, breathe, and drink. We can shower or remove toxic ammonia, but an aquarium fish has to live in a closed environment. What goes in stays and will poison your fish if it is not removed or rendered harmless. That’s where the nitrogen cycle comes into play.
We call it the nitrogen cycle, because toxins like ammonia and nitrite are nitrogen compounds, and those are all the chemical words we need for now. Another big word is little bugs, which some people call bacteria. Bugs are everywhere, and some of them are very good for your aquarium. In fact, different types of insects eat the toxic ammonia and nitrites that fish, uneaten food, dead plants, and the occasional curious cat put into the aquarium.
When your aquarium has enough good bugs, they will convert all the toxins into plant food. Almost like magic, the good bugs enter your aquarium. All you need to do is feed them and give them a few weeks to grow BEFORE adding fish. Good little microscopic bugs will eat flake food or even small pieces of raw shrimp or fish. They mainly live in gravel and filter elements, so if you have an old filter or gravel from an established aquarium, try using some in your new aquarium. You may be able to speed things up by adding one of the products that contain inactivated bacteria. However, the process will still take some time.
The main task of the aquarist while all those good bugs grow is to wait a few weeks. Waiting gives him the chance to get a test kit to measure at least ammonia and nitrite, and do some research on the species of fish he wants to keep. They all need different things. You can also add plants and operate the light and filter, but NO FISH YET.
After all that difficult waiting, you can test your water for ammonia and nitrite. When both measurements stay at zero for a couple of days, the nitrogen cycle is working and the aquarium is ready for fish. The bacteria colonies will grow large enough to handle the toxins, but they can only handle a limited amount, so don’t overwhelm them with too many fish or too much food. If everything works as it should, you will have a well-balanced aquarium. To maintain that balance, change about 20 percent of the water each week, and don’t forget to use a good water conditioner.
