I've set up a 20 gallon tank that I intend to use as a quarantine tank from time to time. Currently, I've got 5 zebra danios in it to start it cycling, and at the moment, the ammonia has gotten up to 0.5 ppm.
I'd like input on two details regarding cycling a tank that is fish only (no plants).
1. If I pull the zebra danios now, and move them into another aquarium, will the tank continue through the cycle since it has some ammonia in it, or is it neccessary for there to be a continuous source?
2. Once the tank is fully cycled, will the bacterial colonies remain even during periods of no fish, or would they just die off due to no food source? I'm sure the biological filter would eventually die off, but I'm wondering how long it can survive with no fish. In other words, how long could the tank go between instances of housing a few fish for a few weeks and still be "cycled" for the next batch?