# Fish Cycling



## missmanatee (Dec 25, 2010)

Hi,
ive been reading alot of the threads and i was just a little confused. what exactly is fish cycling? i just wanted to make sure i really know about it cause i just set up a 25g with no fish/plants yet. thanks!:goldfish:


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## beaslbob (May 29, 2009)

missmanatee said:


> Hi,
> ive been reading alot of the threads and i was just a little confused. what exactly is fish cycling? i just wanted to make sure i really know about it cause i just set up a 25g with no fish/plants yet. thanks!:goldfish:


It can be confusing especially since I showed up. *old dude

The normal bacteria based nitrogen cycle is:

ammonia->nitrIte->nitrate

So when you have a new setup and add fish you get spikes of those parameters in that order. Ammonia is particularily bad and the reason for great stress and death to new fish.

And that is the standard cycle mentioned at aquarium shops, in books and manuals, and on these boards.

Well the I come along and screw things up by adding plants.

Plants prefer to consume the ammonia being generated and therefore prevent that nice organized bacteria only process. What happens instead is there is no ammonia nor nitrIte spike but an initial possible nitrate spike along with lower pH.

Then as bacteria build up and consume the ammonia and the plants are forced to use nitrates for nitrogen. So after a few weeks nitrates drop down and pH rises. So that drop signals the "cycle" has completed. Even though there was no ammonia nor nitrIte spikes.

So if you use plants it is possible to use fish to establish the nitrogen cycle with no dangerous ammonia nor nitrIte spikes.

just my .02


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## beaslbob (May 29, 2009)

Or fish cycling is just using live fish to establish the nitrogen cycle


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## jrman83 (Jul 9, 2010)

The cycle starts when a source of ammonia is present. This can either be supplied by placing fish in the tank (comes from their waste), or by dosing the tank with ammonia. One way is to cycle the tank with fish, the other without or fishless.


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## snail (Aug 6, 2010)

We could do with a sticky on this one. Here are a couple of threads that talk about it, hope it helps: 
http://www.aquariumforum.com/f2/fishless-cycle-9364.html
http://www.aquariumforum.com/f2/nitrogen-cycle-dummies-8164.html


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