How long can I NOT add fish after cycle

So this may be a backwards questions that I have never wondered about.

I have just completed the cycle of my newest tank. After overdosing Dr. Tims ammonia it was at 5+ppm for a week but has come down to 0 and left me with quite some nitrates. Now i'm not sure yet if i want to add more fish to this 25 gallon than just a clown couple, but that couple isn't coming in for another month.

So, since my tank is cycled, what would happen if i just put in coral but now fish after the WC? will the absence of ammonia cause the bacteria to die off again and make me go though another cycle after the clowns are added?

Should i just throw in a firefish or royal gramma for the time being? Also keeping in mind that its better to add clowns last so its better to take some fish out then to add them later.
As @BeanAnimal said, the cycle never really ends. The bacteria need a source of ammonia to maintain their population numbers, however. Adding coral food/reef roids or whatever is a great source of ammonia for the bacteria. If you keep the tank fallow (fishless) and then add some number of fish later, you’ll see a small spike in ammonia/nitrites, but the existing bacteria populations will grow to quickly eliminate it. The result is a “minicycle”, but it won’t harm your tank health. The key is to add them slowly as opposed to going from fishless to fully stocked in one day.