I have a 55-gallon FOWLR tank that has been running for years now. I have long-term residents of a Foxface, longnose hawkfish, sleeper banded goby, a flameback and a clownfish. In the way on inverts I have 2 conchs, 10 blue leg hermits, and 3-4 nassarius snails. Do you think the tank is at max compacity or can I add another fish (I would like a small puffer like a blue spot.)