Fish In Nitrogen Cycle Simplified


Fish in Nitrogen Cycle Simplified: No bottled Bacteria added

The cycle needs an ammonia source. In your case that ammonia source is your fish. They are in there eating, breathing and pooping. All those things produce ammonia. That ammonia is food for your cycle but can be deadly for the fish. You can't know how high the ammonia is without testing it. I highly recommend the API Master Freshwater Test Kit. With it you can know exactly what is happening with the tank water and can do water changes to keep the ammonia/nitrites down to safer levels. Without it you can't know how high the ammonia is so you need to be doing water changes every day to keep it down to a safer level.

A nitrogen cycle is simply growing ammonia and nitrite eating bacteria. That bacteria grows mostly on your filter media but also grows on every surface in your tank.

It takes time for the bacteria to start growing. The first bacteria is one that eats ammonia. The waste from the ammonia eating bacteria is nitrite. The second bacteria is one that eats nitrites. Then the waste from the nitrite eating bacteria is nitrate. There usually isn't another bacteria to eat the nitrates so they have to be removed with water changes. Nitrates are the final stage of the cycling process so unless you have them in your source water you probably won't see them until the nitrites rise and start to fall.

Right now the most important thing you can do to protect your fish is to keep the ammonia and nitrites (once they start showing up) as low as possible with water changes. Water changes will not hurt nor slow down the cycling process as long as you use a water conditioner in the water you are replacing and making sure the temp is close to the same as what you took out. The bacteria you are growing doesn't live in the water so changing it as often as necessary to protect the fish isn't detrimental to the cycling process. Removing a lot of the ammonia with water changes may slow the process down by a few days but is necessary to keep your fish safe. Getting the tank cycled is important but the safety of your fish has to be your top priority.

Ammonia can build up pretty fast so it is possible you will have to do water changes every day or every other day to keep it as low as possible. Low enough to not even show up in the test is ideal but is often difficult to achieve so try to keep it down to no more than .50

I both use and can't over stress the importance of SeaChem Prime while doing a fish in cycle. It is first and foremost a water conditioner but it has the added benefit of neutralizing low amounts of ammonia thus protecting your fish from its damaging affects yet leaving some there to feed the growing bacteria.

A fish in cycle is totally doable as long as your have a test kit, Prime, lots of time and a willingness to do as many water changes as needs to be done to make sure the fish are never in danger.

Contrary to some things I have read one never has to see an ammonia spike during the cycling process. While cycling my last tank I never saw an ammonia spike because I was doing 30% or more water changes every other day for most of the cycle and every day when the nitrites spiked. I know the ammonia was there because the tank did in fact cycle from a dry tank to a complete cycle within 6 weeks with no fish losses.
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Thank you for writing this up mattgirl. It will be a great resource for those who cycle this way by choice or chance.

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