The patio in our gated area to our front door has a water fountain type thing. I tried measuring it and it is about 62 inches high, a little more than 3 feet long ( the water holding length area) and the water is about 14 inches deep. My dad says he doesn't know how many gallons it is. It hasn't been used in a couple of years and has just been sitting there with water inside of it and algae that needs some removing, and mosquito larvae is in it right now lol. So I was wondering if I cleaned it out, drained it, and everything and replaced it with dechlorinated water, could I add a couple of feeder gold fish or something too it? It has the water flow so maybe that could act as a filter, as it has 3 stages it falls from with a light at the bottom. Its a pretty big water basin (is that what you call it) and I'm guessing it can hold more than 20 gallon, probably 40,. Its not final yet as I have to convince my mom and dad too let me do it, but I just need to know if it can be done. I will add a picture that kind of looks like it since I don't have my phone but don't look at the middle just look at the structure as the way the water falls and stuff is different(it is basically the same structure but mine is bigger, and has 3 water fall bowls going vertical. It won't have a heater, at least not until winter time, so.. Can I do it? PLEASE ask any questions!!