Cycling a new aquarium is really important and a lot of problems commonly encountered by beginner aquarists can be avoided by devoting some time to the cycling process. Filling your aquarium with water, tossing in some water treatment and then crowding the tank with fish the very next day is not the best way to go about if you want your fish to thrive.
The aim of the cycling process is to establish large colonies of beneficial bacteria in your aquarium. To learn more about why this is so important, please take a look at the article “Filtration, part 2 – The difference between mechanical, biological and chemical filtration”. You need two types of bacteria in your aquarium. The first type converts the ammonia excreted by your fish into nitrite. The second type converts the highly toxic nitrite into less harmful nitrate.
The most commonly used form of cycling consists of introducing just a small amount of fish to your new aquarium. They will start producing ammonia, thus promoting bacterial colonies to start growing. Since there are only a few fishes in the aquarium, the water mass will be able to dilute the waste products to low levels while the bacteria are busy multiplying. Choose sturdy fish species, since the levels of ammonia and nitrite usually get quite high before the cycling is finished. As the bacterial colonies grow larger, you can gradually add more and more fish. If you want to speed up the cycling process, you can introduce bacterial colonies instead of relying on bacteria brought by the fish. The right type of bacteria can be purchased from a pet shop. You can also use gravel or filter media from an already established aquarium, but by doing so you may involuntarily introduce malicious microorganisms as well.
Fishless cycling requires no fishes to bring bacteria, produce ammonia and act as guinea pigs. This method is still quite unusual, but more and more aquarists are beginning to use it since you do not have to purchase sturdy cycling fish. If you want to try fishless cycling, you will need a testing kit, the right types of bacteria and a source of ammonia. As mentioned above, beneficial bacteria are found in gravel and filter media from established aquariums, and can also be purchased from pet shops. The source of ammonia can be pure ammonia, fish food or a piece of shrimp or similar. When you have introduced bacteria and added ammonia to your aquarium, you have to check the levels of ammonia, nitrite, and nitrate regularly to monitor how the cycling process is going.
Silent cycling is also a comparatively uncommon cycling method. It uses aquatic plants to bind nitrogenous compounds instead of relying on bacteria to convert dangerous nitrogenous compounds into less dangerous nitrogenous compounds. Silent cycling is only possible in a densely planted aquarium with thriving plants, and you should, therefore, avoid sensitive species and instead go for sturdy and fast growing plants that will consume a lot of nitrogen. Use your test kit to carefully monitor the cycling process.