I use a small-medium food storage tub filled with water and a few fake decorations in it, no filter but I use a very small pump to create a small fountain (just a water stream, nothing fancy). It's sort of half-buried so it's really easy to take out and change which I do every single afternoon. The rocks/etc I just dump into a strainer and rinse when I change the water, it's pretty simple but I think it looks nicer than a place old dish.