Cycling Your Aquarium


Your aquarium is an environmentthat will contain certain organisms (fish, invertebrates, plants, etc.). These creatures produce waste which is ammonia (NH3). Ammonia is lethal to fish and at certain levelswill kill them.

What does it mean to cycle an aquarium?

When you first purchase and setup your aquarium it is a sterile environment. As the fish start to produce waste (ammonia) there is nothing to neutralize it. Nitrifying bacteria naturally grows in the tank and it consumes ammonia and produces nitrites. In your sterile tank it will take time for those bacteria to grow.Additionally, you have to wait for nitrifying bacteria to grow. These bacteria consumes nitrites and produces nitrates.

So what does this mean to me?

The more fish you add during the first month of your aquarium’s life, the higher ammonia will get. Therefore, during the beginning of your tank, we recommend that you add a small number of fish to the tank. An easy rule of thumb would be to take the total gallons of your tank and divide it by 10. Start with that manyfish.


Setup a 30 gallon tank → Add 3 fish to start

How long do I have to wait before adding more fish?

The complete cycle of the tank will take ~ 38 days to complete.

After 38 days the tank will have a culture of nitrifying and nitrifying bacteria which will consume the fish waste.

Is the cycle harmful to my beginning fish?

Yes, the high levels of ammonia and nitrite that will be present in the beginning of your aquarium’s life is stressful to the fish and could potentially kill them.

There are two main ways to cycle the tank:

1.Canary in the coal mine

As described above you can start with a small amount of fish that will cause your tank to cycle. One should start with hardy fish that are strong enough to get through this cycle.

2.Fishless cycling

The main reason we have to add fish in the beginning is so that ammonia is introduced into the tank which will cause the bacteria to grow. Instead of adding fish you could simply add ammonia. To do this you need pure ammonia with no added chemicals. You will add ammonia into the tank and test it to make sure you keep the tank at 2-4ppm of ammonia. You will t hen monitor the water to ensure that your cycling is proceeding as described above.

Written by,

Greg Schneider

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Showing 4 comments
  • Steve Makname

    Thank you for the information you provided! It helped us a lot to curve our sons expectations and setup a thriving ecosystem that we all enjoy!

    • admin

      Glad to hear your experience was pleasant! I hope you added your name to our tank drawing while you were in for a chance to win the 45 gallon bow front setup!

    • Azia

      That hits the target peflyctre. Thanks!

  • Arnie

    That’s a nicely made answer to a chlnaelging question

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