I am quite aware of proper godfish care. Mine live in an outdoor pond in summertime and in a large indoor tank in winter. The one without a filter is the runt, Depot, who lives in a two gallon during the fall and winter and in the pond with the others come spring and is quite active and seemingly happy being the center of attention on my desk where se gets treats and has even learned to jump and take food from my fingers. She gets her water changed quit often so that the ammonia levels don't build up.

BTW, my male betta hates it when I clean the gravel and upset the water in his tank, I think a filter would be the death of him as he'd be so stressed out.