The answer to your exactl question is your tank is pretty full.
Now for some unsolicited advice...
Your tank is too small for the Foxface, the Blue Hippo, and the Sailfin. Remove these fish and put in something other than tangs and rabbitfish, as a 75 is too small for any species of either. I'd suggest small reef fish such as Royal Gramma or Blackcap Basslet, Sixline or Fourline Wrasse, maybe another goby like a firefish or scissortail, chromis, etc.
I'd plan for no more than about 6-7 small fish in a 75.