I'm building a pond for my turtles and I might try to keep them out there year round. In that case, the 150 I was going to use for them in the winter is free. I've never had oscars before but I think they're really awesome fish, I had a friend with a big one. How many could I get into a 150gal? I'm thinking probably 3-4, I'm going to have a big wet/dry system set up underneath it, with obviously lots of mech filtration inside.