I'm new to the marine hobby and even though it can seem overwhelming, I love it so far. I have a 30 gal thats been up and running for a little over a month now and just recently purchased a pair of osc clowns. I've been given advice on all sorts of good beginner fish - my question is when do you "graduate" to the next level of fish? If I stock it with a few more fish, do I get more "beginner" fish?