Cycle Tank

Question
Ron,
The Oscar is currently in a 20 Gal tank.
I also don't want to destroy the 20 Gal tanks current biological set-up, by draining it. I guess once the Oscar is moved to the 55 Gal, I will need to have a fish in the 20 Gal, to keep it biologically sound. I may be overthinking this process, but I am trying to get a better understanding of the bacteria that is working behind the scene.
I want to take full advantage of the currently cycled 20 Gal tank.  
Thanks again...
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Followup To

Question -
Hi Ron,
I have just set-up a new 55gal. tank. I have an existing tank with an Oscar in it. I would like some advice on how to cycle the new tank, to prepare it for the Oscar. I understand I can use some filter material from the existing tank, but what do I use to create the ammonia?
Thanks a lot...

Answer -
Hi Blake,
  Actually, all you need to do is take about 20 gallons of water from the old tank and put it in the new tank and that will do it.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


Answer
Hi Blake,
 You are overthinking it a bit.  Take 10 gallons from the 20 gallon tank, put that in the 55 and you will be set with the new tank and the old tank will be fine as well.  

 The bacteria are actually pretty robust.  You just need to get them started in the new tank and they will do the rest.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>