Whether you’re interested in keeping axolotls or fish, a desktop shrimp tank or a massive community set up, cycling your aquarium is an important first step!
First Thing First, What, Exactly, Does “Cycle an Aquarium” Even Mean!?
Hey, don’t laugh, everyone has to start somewhere! I remember when I was a teenager, researching to bring home my first betta fish. I didn’t know what it meant to cycle an aquarium either. If you’re thinking about getting a freshwater pet, and you’ve found yourself on this page, than you’re in the right spot! Cycling an aquarium might sound like some complicated, intimidating process at first. And, while it is a process, learning more about it can turn intimidating into easy-peasy!
As basic as it gets, cycling an aquarium is the process of letting good bacteria establish in your aquarium, so they can do (a lot of) the dirty work for you! Bacteria colonies inside your aquarium will help break down toxic waste products into less toxic substances that can be removed via regular water changes, or even utilized by the live plants in your aquarium! Think of the bacteria in your tank as a natural filtration system. It works to keep the water your wet pet lives in clean and safe. To go into a bit more detail, we’ll need to take a look at the nitrogen cycle…
The Nitrogen Cycle
Food you feed your aquarium pet is either consumed by your pet or, as is often the case with overfeeding, collects in your aquarium. Poop and rotting food both cause a chemical called ammonia to build up in your tank. Ammonia is toxic to our fishy friends. If enough of it builds up in your tank, it can cause serious health conditions, and even death (death is a pretty serious health condition am I right!?).
Luckily, there are types of bacteria that can colonize our aquariums and break down this potentially deadly ammonia. But don’t get too excited. These bacteria are able to convert ammonia to another chemical called nitrite. You know what sucks? Nitrites are toxic to aquatic animals too! Bummer, right?
Well, thankfully, yet another type of bacteria is able to take those nitrites and turn them into nitrates. While high levels of nitrates are not good for aquatic animals either, they are much less toxic than ammonia and nitrites. The great thing about nitrates, or at least I think so, is that it can serve as fertilizer for aquatic plants. In a planted aquarium, healthy plants will remove nitrates from the water, ensuring that the nitrate levels don’t get high enough to hurt your aquarium inhabitants. In addition to potentially fertilizing plants, nitrates can be removed from your aquarium via simple water changes.
I always recommend regular water changes, even in heavily planted aquariums. Because remember, although they are less toxic, you don’t want a massive build up of nitrates in your tank. Unless you’re measuring your nitrate levels regularly, there’s no way to guess exactly how effectively your plants are doing the job of removing it. Plus hey, water changes can be relaxing and you can use cleaning your aquarium as an excuse to get out of doing other things you don’t want to do!
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Back to Cycling Your Aquarium…
Cycling an aquarium is basically just setting up your aquarium, and giving it enough time that beneficial bacteria colonize it. Sounds easy, right? It is, for the most part. But how long does it take to cycle an aquarium? What, exactly, do you have to do to get it to cycle? How will you know when it’s cycled!? So many questions! Lets answer them.
How to Cycle Your Freshwater Aquarium
Set up your aquarium. Make it awesome! Set up the filter, heater, everything you’re planning on having set up once you add your aquatic pet. Then, and this is going to sound weird but, feed your aquarium. Add fish food, axolotl food, whatever pet you are getting food, into your empty aquarium. It feels weird, I know, feeding nothing. But you’re not really feeding nothing. You’re feeding bacteria that will begin to colonize your filter, and other surfaces of your aquarium. Just let the food sit. Don’t overdo it, a little bit is all you need. You basically want it to rot in the tank, as gross as that sounds, because then it will begin to produce the ammonia that your beneficial bacteria need to thrive.
Alternatively, you can actually purchase ammonia and add that to your tank instead. This is how all the cool kids cycle aquariums these days. If you purchase ammonia marketed for cycling an aquarium, it will come with instructions on exactly how much ammonia to add per gallon of aquarium water. You want to add enough ammonia that your ammonia concentration reaches 2 mg per L, or 2ppm.
Oh and, alternatively alternatively, if you’re lucky enough to already have an established, cycled aquarium, or know someone who does, you can totally cheat this process a bit. If you take a filter, or a bit of filter media, out of an already established aquarium and add it to your new tank, you’ll be instantly introducing all the good bacteria you need into you new tank. These days, you can also purchase aquarium bacteria! Neat right? Purchasing bacteria or using an already established filter will really help speed up the cycling process.
While cycling your aquarium, you’ll need an aquarium test kit. I recommend this API test kit for two reasons. One, because liquid test kits, if used properly, are more accurate than dip sticks. And two, because the liquid kits totally make you feel like an awesome mad scientist!
How Will You Know When Your Aquarium is Cycled?
This is why you need that test kit! Aquarium test kits can tell you how much ammonia, nitrite, and nitrate are in your tank water. A few days after setting up your tank, and adding either food or ammonia, test your aquarium’s ammonia levels. You’ll want to see levels at at least 2ppm. If your ammonia levels are lower than that, add more food (or ammonia), wait a few days, and test again. After around a week or so, especially if you are consistently seeing your ammonia levels decrease, start testing for nitrite as well as ammonia. Remember, the first step in the nitrogen cycle is ammonia getting turned into nitrite. So, you’ll eventually want to see your ammonia levels going down, but your nitrite levels going up. Congratulations, you are now the proud owner of a tank of bacteria!
Keep that ammonia level at or above 2 to 3ppm though! Remember, nitrite is toxic to fish and we don’t really want it in our aquarium. Keep testing your aquarium water. Eventually, you should see your nitrite levels begin to drop. That’s when we can start testing for nitrates. Nitrates are what we want! It means you have all the necessary bacteria to cycle your tank. If your nitrate level raises to above 40ppm, it’s time to do a water change. Remember that there are no bacteria that take care of the nitrates, so that’s on us. But, in a fully cycled aquarium, you’ll want to see readings of zero for both ammonia and nitrite. Not because they aren’t still being produced, but because the bacteria are eating them all up!
Because I tend to be so long winded…in short, you’ll know your aquarium is cycled when you see readings of zero for both ammonia and nitrite, and some number above zero for nitrate! To test your cycle, raise your ammonia levels to 2ppm. Within 24 hours, you should see the ammonia levels drop from 2ppm to zero. Nitrite levels should also be zero at the 24 hour mark.
How Long Does it Take to Cycle an Aquarium?
It takes however long it takes. Sorry to say, but cycling an aquarium isn’t an exact science. It’s frustrating, I know. You’re probably sick of looking at an empty aquarium, am I right? But a cycle can take an average of a few weeks, to a few months, to complete. And believe me, for the health of your new aquatic friend, it’s worth the wait!
When Can You Add Your Pet To Your Newly Cycled Aquarium?
Well….once your aquarium is cycled, sort of. Be careful! The bacteria colonies in your tank will be used to processing a certain amount of ammonia. Adding about a billion fish to a newly cycled aquarium is never a great idea, because while you may have the proper bacteria present to cycle your aquarium, you may not have enough of them (yet) to deal with a huge bio-load. Add new inhabitants to your tank slowly, a few at a time if you’re setting up a community tank.
If you’re adding any type of pet that’s big and messy, such as a goldfish or axolotl, you’re going to want to keep a really close eye on your ammonia/nitrite/nitrate levels for a while. It may take time for your bacteria colonies to grow enough to handle how much waste your larger pet is producing. If you notice any ammonia or nitrite in a newly cycled tank with inhabitants for the first time, or very high levels of nitrate, water change, water change, water change! You’ll probably have to do water changes more often after first introducing your new pet to his/her home, but over time your bacteria numbers should adapt, so you can change water less frequently.
And That’s It?
Is that all? You thought I said this wasn’t going to be complex! But really, once you get the hang of cycling an aquarium it’s really not a big deal. And once you have one cycled aquarium, throw an extra sponge filter in there. That way, when you get that second tank (and you will get a second tank, aquarium keeping is an addiction), you’ll have a filter ready to go to make cycling your next tank all the easier. Good luck! Feel free to contact us if you have any questions. May the aquarium cycling bacteria in your tank be forever bountiful!