The new aquarium. Truly a momentous occasion in any household. Now that it’s home and out of the box, and you’ve followed the instructions on how to set up the filter and put the stand together, what’s next? Well, fill it up and throw some fish in and start enjoying their fishy antics, right? Not quite. First you have to watch some capital-s Science happen.

Before we get into cycling your tank and the Nitrogen cycle, a quick note that every time you add water to your tank (via a bi-weekly water change or the initial fill), be sure to condition that water. (You can use any product that will remove the chlorine from tap water.)

Now that your (hopefully) 20 Gallon or larger tank is full with conditioned water, has gravel and rocks and other decorations in it and is being filtered properly you need to kickstart the Nitrogen Cycle. Depending on your animal rights standpoint, this can be done with feeder fish or chemicals. If you decide to use feeder fish (as i did), bear in mind that they will die what is most likely a horrible fishy death (but for my money they were going to be eaten anyway, so at least this is a survival of the fittest contest, as evidenced by my lone survivor). Go to the local pet store and ask for a dozen fish feeders. These are the fish that you always see in that one huge tank and there’s about a million of em in there, and they all look like small orangey goldfish. This should cost you no more than $3 or so. If they charge you too much more than that, find a better pet shop. While you’re getting your little troopers, also pick up a test kit. I prefer the one-stick multi-test strips. People don’t like these because they’re not as exact as the test tube variety, but for my purposes it tells me all I need to know.

Bring your little copper soldiers home and just plunk them in. I’ll discuss the proper methods for introducing your “real” fish to your firmly established aquarium later, but for now just chuck them in as your aquarium is about to get really toxic anyway.

Watch them swim. So happy. So thrilled they aren’t being eaten. At this point you can stand over your aquarium and laugh maniacally while your girlfriend/boyfriend/spouse shakes a tin sheet to simulate thunder sounds. This is optional, but I feel like it drives the point home. These fish are now running on borrowed time.

Take your first test strip out and record the information. The important info is:

pH — Nitrate — Nitrite — Ammonia

Your pH is going to stay mostly the same and is a wise thing to know. The ideal is around 8.1 - 8.3. Mine runs a little lower than that, but it’s better to keep the pH constant than try to keep it up and have it fluctuate. Fish are good at adapting as long as the conditions remain the same.

Now, the other three things all have to do with nature’s miracle: The Nitrogen Cycle.

Now that your fishies are eating, the next logical thing they’ll have to do, according to prominent author Taro Gomi, is poop. This is what we want. We want them to throw a poop party and invite the poop King over to add more poop. This poop is key to getting the whole aquarium underway.

Poop gives off ammonia. Massive amounts of ammonia are the first step to the process. Test the water every week and pay special attention to the ammonia. You’re waiting for the ammonia to spike to ludicrously high levels. Once the ammonia has risen to toxic levels, you’re through with step 1. This is the most dangerous part for your brave little fishy friends. At this point, I like to dress up like JFK and stand atop my tank and proudly monologue to them, “Ask not what your tank can do for you, but what you can do for your tank.” And other such inspirational speeches. Some of them are just not going to make it. Know this.

In about another week, you should start to see the ammonia levels start to go down. Simultaneously with this, you’ll see the Nitrite levels rise. This is where things get complicated. There is bacteria in the air that will begin to form colonies in your tank. The first kind will convert ammonia to nitrites. Nitrite is still toxic to your fish and is still unwanted in your tank. But as your ammonia levels fall, your nitrite levels will rise as the bacteria eats the ammonia. This will take another week or so.

Let’s take a quick sidebar and discuss what’s going on at this stage. There are two kinds of nitrogen-related items that begin being produced here. The first is Nitrites, with an “i” N-I-T-R-I-T-E-S. These are dangerous for fish and other life and need to be further broken down.

As your NITRITE levels rise, other, better bacteria will begin to form colonies in your tank. These little guys will break down NITRITES into NITRATES. Nitrates are what we’ve been looking for the whole time. These are non-toxic and will not harm your fish. So now as your NITRITE levels begin to fall, you will see your NITRATE levels rise. This will take another few weeks.

The end of all this should be 0 Ammonia, 0 Nitrites, and a safe level of Nitrate. Once you have achieved this, I would let the tank roll for another week or two before adding my “real” fish.

Well, congratulations, you’ve let your tank cycle and are a responsible fish owner. Now please take the time to help anyone else setting up a tank and keep them from posting “My fish died after I dropped them in my brand new tank that I just filled with tap water” on the internet.

Knowing is half the battle.

This entry was posted on Wednesday, January 3rd, 2007 at 8:17 pm and is filed under . You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.