What kinds of freshwater animals can live without filtration?that you get at a pet store?
If your tank is superbly planted (with live plants, of course), you could try shrimp, especially some of the hardier species like Ghosts, Red Cherries, Crystal Reds, Crystal Blacks, Amano/Japonica, and most others, but you would still need to perform the occaisional water change to remove the nutrient buildup and replace essential trace elements. Just remember that even though there’s no fitler, it is NOT an enclosed ecosytem and should not be treated as such. EDIT: Turtles and frogs produce huge amounts of waste, making them terrible choices for an unfiltered tank. Also, mudskippers require brackish water, which will likely separate if left unfiltered. EDIT 2: What is even more annoying to Bettas than getting blown around by a filter (which can be adjusted by covering the intake with a water permeable item like pantyhose, filter floss, or a sponge) is ammonia poisoning followed by a complete water change, which is what they’ll get without a filter. Ammonia poisoning combined with 100%
