Please don't use a fish to cycle the tank, it's cruel. And definitely not in a 10 gallon tank, if you are talking about the same tank as your other thread.
Chili rasboras do better in a heavily planted tank, so you can cycle it using plants then let it run for a few months with just the plants to let it mature.
So ya got yourself a fish tank, and now you're wondering how to cycle it. You have a few options: 1) Fishless cycle: Set up your substrate and filter (decorations and plants are optional), buy pure ammonia, add enough to your tank to read 3ppm, wait. Full instructions here...
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