Have patience?

[Naked Wookie]

personally I would only add maybe the goby to go along with the 2 clowns you got.
most people I have talked to recommend firefish for 30g up tanks cause they are extremely active swimmers, I know my 2 I had in a 25g reef used up all the open water darting around.
its alot easier to go with a light bioload starting out rather then having to much and crashing the tank and hating the hobby,it happens to often.
so 5 fish in a 20g seems awful cramped.