I have a pair of clowns, the Orange goby, and Cardinal. All are suitable for a 40. Never really messed with the damsels because of aggression. Make sure you have a cover gobys tend to be jumpers. Super easy to make screen cover from a hardware store. YouTube it.
I have a starry blenny too and is one of my favorite. A ton of personality and goes after algae along with smashing on mysis. Might be worth checking it out
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