Part 1 of 11 Aquarium Start Up Guide: Starting Your Aquarium Journey & Understanding the Nitrogen Cycle

Setting up a successful saltwater or freshwater aquarium is like crafting a delicate balance between art and science. Welcome to our 11-part series, designed to help you navigate the intricacies of establishing and maintaining a vibrant aquarium ecosystem. To kick things off, let's dive deep into one of the most crucial aspects of aquarium care: the nitrogen cycle.

What is the Nitrogen Cycle?

The nitrogen cycle is a natural process by which harmful waste products in your aquarium are converted into less toxic compounds. This cycle is essential for maintaining a balanced and healthy environment for your aquatic inhabitants.

Stages of the Nitrogen Cycle:

1. Ammonia (NH3) and Ammonium (NH4+):

• Source: Waste from fish, uneaten food, and decaying plant material.

• Importance: Ammonia is highly toxic to fish and must be converted to safer compounds.

• Bacteria Involved: Nitrosomonas bacteria convert ammonia into nitrite.

2. Nitrite (NO2-):

• Source: Conversion of ammonia by Nitrosomonas bacteria.

• Importance: Nitrite is also toxic and must be further broken down.

• Bacteria Involved: Nitrobacter bacteria convert nitrite into nitrate.

3. Nitrate (NO3-):

• Source: Conversion of nitrite by Nitrobacter bacteria.

• Importance: Nitrate is less harmful but should still be kept in check through water changes and plant uptake.  From our water parameter post recall that nitrate levels should be kept below 20-40 ppm (parts per million) for freshwater tanks and 5-15 ppm (parts per million) for saltwater corals and invertebrates. More on how to control this through maintenance in our maintenance blog.

Why is the Nitrogen Cycle Important?

Understanding and managing the nitrogen cycle is crucial because it directly impacts the health of your fish and overall aquarium stability. An imbalanced nitrogen cycle can lead to toxic build-ups, stressing or even killing your aquatic life.

Commonalities in Freshwater and Saltwater Aquariums:

• Bacteria: The nitrogen cycle involves the same types of bacteria (e.g., Nitrosomonas and Nitrobacter) in both freshwater and saltwater environments.

• Process: The stages—ammonia to nitrite to nitrate—are consistent across both types of aquariums.

• Importance: Regardless of the type of aquarium, maintaining a balanced nitrogen cycle is essential for a healthy ecosystem.

Cycling Your Aquarium: Fish-In and Fishless Techniques

• Properly cycling your aquarium is key to establishing a healthy environment for your aquatic life. You cant just go adding any fish or coral to your aquarium the minuet you put water in it.  You have to give the ecosystem your setting up time to culture (grow) balanced levels of Nitrosomonas and Nitrobacter bacteria.  This takes time.  Patience in this hobby is your biggest factor to success! The slower you go the more time you allow for these bacteria populations to balance out and the better off you will be both in the initial cycle and by adding livestock after the cycle.  There are three ways to cycle your aquarium: fish-in, fishless cycling and long term sit and wait methods.

Fish-In Cycling

Overview: In this method, fish are used to kickstart the nitrogen cycle. It's crucial to proceed with caution to ensure the safety of your fish and only put in small numbers or the toxic compounds will rise too high and kill everything.  The benefit here is it gives you fish to watch right away but there is risk you may kill them.

1. Choose Hardy Fish:

• Opt for resilient fish that can tolerate higher levels of ammonia and nitrites, such as zebra danios or hardy cichlids in freshwater or clowns and damsels in saltwater.

2. Test Water Parameters:

• Regularly test ammonia, nitrite, and nitrate levels using a reliable test kit.  You will see each rise and fall and we recommend testing weekly.  This process can take about a month. 

3. Monitor Fish Health:

• Keep a close eye on your fish for any signs of stress or illness and adjust care as needed by possibly doing water changes.  You need to take action when ammonia gets higher than 5-8 parts per million (ppm).  Levels above 8 ppm is likely to stress or kill your fish.  The key to success here is only to feed every other day very little or toxic levels will spike to lethal levels. 

Fishless Cycling

Overview: This method involves establishing the nitrogen cycle without any fish, reducing stress and potential harm to live inhabitants.  You need to buy additives to put into the aquarium and this is by far the fastest way, usually 21-28 days.

1. Add Ammonia Source:

• Introduce a pure ammonia source (ammonium chloride or household ammonia without additives) to start the cycle.  This can be purchased in your local fish store or online.  Your target is about 5 parts per million (ppm).  Adding more ammonia than that and the bacteria seems to grow slower and take longer.   

2. Add Beneficial Bacteria:

• You can find bottled beneficial bacteria at your local fish store or online.  Some products like Dr. Tim’s or Fritz work well.  We recommend purchasing enough to dose the initial amount and then through the cycle to continually add as it goes through the process.

3. Set Up Testing Schedule:

• Test water parameters regularly on a weekly basis to track ammonia, nitrite, and nitrate levels.  You will observe them rise and fall. 

4. Monitor Bacteria Development:

• Watch for the appearance of nitrites, followed by nitrates, indicating that beneficial bacteria are establishing themselves.  Water may be cloudy as the bacteria “blooms” and the water may even have a slight odor to it. 

5. Maintain Ammonia Levels:

• Keep ammonia levels consistent to ensure a steady food supply for nitrifying bacteria.

6. Wait for Stability:

• The cycle is complete when ammonia and nitrite levels drop to zero, and nitrate levels rise.

Sit and Wait Cycling

Overview: This is pretty much as it sounds.  Set up the tank and put a pinch of food in every day or put a piece of shrimp in the aquarium.  This decays and ammonia builds starting the cycle on its own.  Because you are not adding anything it this can take months but it is the most cost effective method. 

Conclusion

Both fish-in and fishless cycling methods have their pros and cons. Fish-in cycling allows you to start with live fish but requires careful monitoring and possible water changes to prevent harm. Fishless cycling takes longer and a higher cost but is generally safer and stress-free for fish as once its cycled the bacteria populations keep the water at safe levels.  Sit and wait is cost effective but takes a long time.  By understanding and implementing these cycling techniques, you’ll be well on your way to creating a thriving aquarium ecosystem.

In future posts, we'll explore other critical aspects of a freshwater or saltwater aquarium such as: Setting up, choosing the right filter, the importance of lighting, aquascaping, common plant or coral mistakes, Top 10 fish for beginners, maintenance, how to deal with algae, understanding fish behavior and common fish diseases and treatment. Stay tuned, and happy fishkeeping! 🐠