Have you ever seen a fish in the wild living in pure, crystal clear water with no other contaminants? Probably not. That’s because life isn’t sterile; it doesn’t flourish in “pristine” conditions, but rather when there’s a whole ecosystem of microorganisms, plants, and animals that are in balance with one another. So, if you’re looking to set up a brand-new fish tank, let’s talk about aquarium cycling and how to prepare a healthy, thriving environment for your fish to live in.
Nature’s way of recycling nutrients is known as the nitrogen cycle. At a very high level, bacteria and plants convert and consume nitrogen compounds from their environment, animals eat the plants and bacteria, and then the plants and bacteria consume the animal’s waste as their food.
In an aquarium, the same thing happens. You feed your fish, your fish produces waste (also known as ammonia), and then bacteria and plants absorb the toxic waste so that the water is safer for your fish to live in. But wait! What happens if you’ve just set up a new aquarium with tap water, gravel, and decorations? Where are the plants and beneficial bacteria that can break down the fish waste? That’s why we need aquarium cycling: the process of making sure that your fish tank’s ecosystem can process ammonia without killing any animals.
For more details about how the aquarium nitrogen cycle works, check out our full explanation here.
There are several ways to cycle an aquarium, and some are easier than others. Based on our experiences of successfully running hundreds of fish tanks, here are the methods that have worked well for us:
This approach is the most common, used by both beginner and veteran fish keepers alike. Most people cannot watch an empty aquarium for several weeks or months, hoping that beneficial bacteria are actually growing. So, here are a few tips to help you get started on the right foot:
Speed up the aquarium cycling process by adding beneficial bacteria from used filter media or additives such as Fritz Zyme 7.
With a water test kit, you can monitor the water quality of your aquarium to ensure your fish are safe and healthy.
A water test kit helps you determine if there are toxic levels of nitrogen compounds in the aquarium.
This method is our favorite because it truly transforms your aquarium into a natural ecosystem, both biologically and visually. Rather than setting up a bare tank with very little to no fish, you can immediately add live aquarium plants and then focus on growing them with good lighting, substrate, and fertilizers. In fact, according to microbiologist Diana Walstad, aquatic plants consume nitrogen waste even more effectively than bacteria. All the more reason to go for a planted tank! (That said, the leaves and roots of the plants will contribute some beneficial bacteria, but you can add even more using the tips mentioned above.)
Once the plants (or algae) show new growth, the cycle is complete. Your plants are successfully consuming ammonia and nitrates and converting them into new leaves and roots. Gradually add a few fish, feed them sparingly, and use the water test kit to ensure that ammonia and nitrites are at 0 ppm and nitrates are below 40 ppm.
A planted tank is not only beautiful to behold but also improves water quality for your fish.
This technique for cycling has gained a lot of interest on the Internet, and it involves placing fish food or other source of ammonia in an empty aquarium to grow bacteria. After helping countless people in the hobby, we don’t recommend this process for beginners, since we find that many new fish keepers typically do it wrong and struggle to complete the process.
However, if you’re set on using this method and know what you’re doing, make sure to seed the tank with beneficial bacteria via used filter media or a bacteria additive because otherwise you’re going to have a long road ahead.
Aquarium cycling requires a bit of effort (and patience) on your part, but trust us – the results are totally worth it. By preparing a welcoming ecosystem for your new fish, you greatly minimize loss of life and make your aquarium maintenance routine easier. For more information, view our video on cycling with a planted aquarium:
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