Please define 'a while'.
You say nitrIte in the title, nitrAte in your post...
If it's a nitrIte spike, you need to do water changes as you want your tank to cycle. The nitrIte will completely dissapear once it has finished cycling.
If your problem is nitrAtes, this is normal and, as long as they remain under 40, safe for most fish. Having said that, a weekly water change, fast-growing plants, less feeding and under-stocking will keep nitrAtes low for longer.
I have to urge you to do water changes and not try to use chemicals in your tank to correct problems - especialy if you don't know the original cause. Many chemicals can affact your water parameters and fish. They are also often unstable and many only offer a temporary solution.
Seriously though, water changes are the BEST way to keep fish healthy. Is there a particular reason you don't want to do water changes? You should only need to do a weekly partial one - if not, you are over-stocked and/or over-feeding.
Water changes can be a great time to interact with your fish... my cories follow the gravel vacuum around, the other fish follow the cories and the danios play in my hands. The actualy swim through my fingers and over my palm if I put it real close to the surface.
