My tank has fish, plants, snails, insects and shrimp, all growing and reproducing, i barely feed and do so primarily to keep the fish breeding and creating fertilizer. The microinverts and fry provide a lot of food. If it weren't for evaporation and the requisite water changes needed from mineral accumulation i'd just let it sit. Water changes tend to be necessary as nature provides rain, floods, and the whole water cycle. You can't close that part off very easily. Excellent light and refuge for fauna are inherent in any more balanced system. A diverse range of habitats support different parts of the foodweb. I only use a filter for water polishing. I use a spatula to agitate the corners and such to occasionally get mulm up into the water column, this usually means a lot of feeding for the predators. Once again this is imitating a natural systems upsets and foragers. It's also very important to not have any filtration that might destroy inverts.
Homebuilt 3'x2'x18" 2:36" Buildmyleds.com Strips with custom diodes, HOT Magnum for polishing on nigth timer, Hydor Koralia watermover, and UV filter with sponge filter intkae also on night timer. No CO2 or ferts. Various plants, shrimp, and tetras all breeding.