I cycled my 55 gallon with 2 zebra danios. Then, after the ammonia went up and down and the nitrite was finally at zero.. i started buying 1 or 2 fish/week. Now 6 months later i have a nicely established tank.
a good friend of mine just inherited a 30 gallon and she is moving this weekend to her new apartment down in Tampa. So she brought over her filter and stuck it on my tank. It's the same filter as mine only a bit smaller, so i cut my sponge in half and put it in her filter, along with her sponge, and i put a new sponge in mine (i also have biomax in my filter) so now i have both filters running on my tank, and im taking her filter to her this weekend, and by that time, my new sponge should be colonized in my tank, and she still has a piece of my old sponge in hers. So this weekend when i go visit her, she will already have her tank set up and we will put the filter on it and it will be ready to stock with fish!