The Nitrogen Cycle & Your Aquarium

The water aquariums looks like, well, water. However, there is an elaborate cycle developing at a microscopic level called the Nitrogen Cycle. If this cycle is not managed properly, your fish can become very sick and even die.

In a nutshell, here is what happens. Fish eat, and then fish excrete waste into the water. Fish waste is very high in a substance called ammonia. Decaying plants and excess food can also contribute to the amount of ammonia in your tank. Ammonia is VERY toxic to fish.

You may have noticed the BIO-wheel in your aquarium kit. This BIO-wheel helps support the growth of good bacteria in your tank. One such colony of good bacteria are known as Nitrosomonas. These bacteria break down ammonia to Nitrite.

Nitrite still makes fish sick, but never fear, another colony of good bacteria called Nitrobacter helps break down Nitrite to Nitrate. Nitrate does not make fish sick unless it is present in large quantities. If the Nitrate levels get too high in your tank, a water change can resolve the problem quickly.

Assignment #2 - Click here to download

With your team, investigate the methods for cycling an aquarium. Develop a detailed plan for cycling your aquarium and prepare a presentation explaining why the method that you developed is the "best method." You will also need to develop a timeline for your process. How will you know when your tank is fully cycled? How will you monitor the process? What supplies will you need? Note: It is important that no organisms are harmed during the cycling process.

Resources

Here are some additional resources to help you research the nitrogen cycle as it relates to aquariums:

• The Newport Aquarium Cycling Protocol - A document from the Aquatic Adventures Academy Curriculum
• Nitrogen Cycle - A document from the Fish in the Classroom curriculum developed by The Florida Aquarium
• Understanding the Nitrogen Cycle in Aquariums
• The Maturation of a Biological Filter
• About.com Freshwater Aquariums
• Mr. Jeff Gibula - Director of Husbandry at the Newport Aquarium

Water Chemistry & Nitrogen Cycle Basics Fishkeeping:
Water Chemistry Basics