Cycling can be referred to as nitrification, startup cycle, biological cycle or the nitrogen cycle. It is the process which is required to keep your fish alive. Cycling an aquarium is the process of growing colony of “good” bacteria which is created by decaying food and fish waste. Unlike nature, the aquarium is an environment in which the water and waste are contained. Over time this can present a problem for your fish. Luckily bacteria can convert over into safer forms which can help keep your fish healthy and alive, these bacteria I like to call “good” bacteria.
The “good” bacteria remove toxins that are currently present in the water which cannot be seen with the naked eye. Without these bacteria, the fish will be affected by the toxins and can cause stress build up to your fish and will eventually every living species in your aquarium.
Beginner Fact: Un-cycled aquariums are one of the leading causes for failure in the hobby.
Three Stages of Cycling an Aquarium
Ammonia (NH3) → Nitrate → Nitrite
Stage 1: Ammonia is introduced into the aquarium (via methods below). Ammonia is dangerous once it reaches 2ppm, which is typically occurs within three days after it is added.
Stage 2: Ammonia is then oxidized in this sage and becomes the byproduct called Nitrite. Nitrite is highly toxic at levels of 1 mg.
Stage 3: In the final stage, the Nitrate converts to Nitrate which are safe at low to moderate levels. As long as the levels are below 10 ppm, the fish are safe. To ensure the fish are safe, periodic water change will alleviate any rising Nitrate levels.
Now that you understand the different stages of the cycling process, you may ask, how do I create this so called “good bacteria”? Well, there are several ways in which you can cycle your tank. Any of these methods identified below have been proven to be successful in the hobby. However, just remember, DO NOT introduce any livestock into the aquarium until the tank has been fully cycled, unless you are using the starter fish method.
Tips: If the nitrates are too high, then perform a daily 20% water change until the nitrates go down to 10ppm or less. Repeat for ammonia.
Required Equipment Needed: Water Tester
Here are the most common practices
After you have setup and filled up your aquarium with water, you can start cycling it with any of the methods below.
Ammonia or Fish Food (aka the “Fishless cycle”): Some hobbyist feels strongly against using other fish to cycle an aquarium due to the suffering that they will endure during the process. As an alternative, using household ammonia or fish food has been as successful in cycling an aquarium. When choosing a household ammonia source, make sure it is ammonia only and/or ammonium hydroxide and/or water in the bottle. It should be odorless, no surfactants and coloration products. You can choose any kind of fish flakes to cycle your tank. This is probably the slowest cycling method.
Step 1: Just drop a small pinch of flake food or few drops of ammonia every day for the next few weeks.
Step 2: Test for ammonia and nitrate levels. Make sure to test every so often for the next few weeks. Typically this could take a month before your tank is fully cycled. During this time, do not perform any water change until the tank is fully cycled.
Step 3: Once you are able to get the readings to zero nitrites, zero ammonia and 10 ppm or fewer nitrates, your tank is ready for fish.
Tips: If the nitrates are too high, then perform a daily 20% water change until the nitrates go down to 10 ppm or less. Repeat for ammonia.
More common practices
Starter Fish:This is another way to cycle your aquarium. While this has been a method used for many years, it may be viewed as cruel as the fish is put through great stress and may not survive. Another reason to avoid using this method is that the fish may contaminate your water by introducing ICH and any other parasites to your new aquarium.
Step 1: Pick up a hardy fish from your local pet store and after properly acclimate the fish, you may place it into your aquarium. The typical feeder goldfish has been a popular choice as they are cheap to replace. You would normally get a batch and replace them as needed.
Step 2: Start feeding the fish and test for ammonia every other day.
Step 3: Test for ammonia and nitrate levels. Make sure to test every so often for the next few weeks. Typically this could take a month before your tank is fully cycled. During this time, do not perform any water change until the tank is fully cycled.
Step 4: Once you are able to get the readings to zero nitrites, zero ammonia and 10 ppm or fewer nitrates, your tank is ready to introduce new fish.
With Right Now Bacteria: This is probably the easiest method, and most expensive! Given that these are live bacteria, make sure that the bacteria have not exceeded its expiration date.
Step 1: Go to the pet store that sells live beneficial bacteria (“good bacteria”).
Step 2: Follow the instructions on the bottle or bag.
Recommendations: Bottled Bacteria
Using media from existing tank: You can expedite the cycling process if you are able to get a cup of gravel or old filter media from their established aquarium.
Step 1: Pick up the gravel, filter media or water from the established tank. Just make sure that the items are submerged with the same water from the tank. This is to keep the bacteria alive until you reach home.
Step 2: Immediately place the items into your tank and DO NOT wash the items.
Step 3: Over the next few days, you need to continue feeding the bacteria so you may follow any one of the methods above.
Step 4: Continue cycling with any of the other cycling methods mentioned to feed the good bacteria.
Cycle with Live Plants: To expedite the cycling process, live plants may be added to the aquarium. I would only recommend this if you are experienced and have done enough research so you have the right environment to host them. Plants in general consume ammonia, nitrate and nitrites which makes the cycling process goes faster.
*Important Fact: Dead plants will release any ammonia, nitrate and nitrite back into the aquarium.