its actually completely possible if you use alternatives. even without water changes.
I have kept some tanks over stocked, somewhere around 50 two inch long fish in a five gallon, without any water changes or filters. but, it did get relatively decent water flow from a small power head and the whole tank was essentially a giant algae scrubber. I was never able to detect any ammonia, nitrite, or nitrate, even though I made sure there was food in the tank at all times(more than they could eat) and I kept the tank at insane stocking levels.
so, if you want to keep a simple ten gallon without a filter, I would suggest an up-flow algae scrubber. it will provide gentle flow, aeration, and the algae will reduce ammonia to minute amounts. plus, if you leave it on at all times and never turn it off, it will keep the water more stable than usual since it puts oxygen back into the water at night, when the plants would be using oxygen and producing CO2.
"The ecologist is continually having to look at the aspects of nature with which he is unfamiliar and perforce must be an amateur for much of his working time.... professionals may carp at omissions, misconstructions, or even downright errors in these pages. perhaps ultimately they may forgive them for the sake of the overall vision that only the amateur, or the ecologist, blithely sets out to experience."G. Evelyn Hutchinson