I still think thats amazing.
I don't think you can keep up with the water quality without some kind of bio filtration, liverock or a hang on the back filter with a sponge in it. In a small tank with that many fish and heavy feeding you would probably have to change a little of the water everyday. I'll bet with some good established liverock and maybe a very small powerhead or HOB filter for circulation you wouldn't have to change the water very much at all. Good Luck!