I started my 13.5 nano in late august, after three weeks I added a lovely pair of clowns that have done fantastic, and have even grown quite a bit. Soon after, I bought a few snails and an urchin, all of which are still alive. then I added a coral banded shrimp that has molted twice since I’ve had him. I just added my first corals 2? Weeks ago and now I am wondering if adding a small goby/firefish would hurt? I have two large chunks of live rock and am planning on grabbing some more to fill in the tank more. What do y’all think? Am I at my limit or is one more fish acceptable?