Saltwater fish overcrowding help?

I am currently setting up a 55 gallon saltwater aquarium. We have a wet/dry filtration system, lighting with four 65 watt bulbs, 60 pounds of dry sand and live sand. We will have around 50 pounds of live rock in the near future. I am wondering if 1 yellow tang, 1 blue hippo tang, a diamond goby, 2 yellow tail damsels and 2 tank-raised maroon clowns is too much. Is there a rule for saltwater aquarium overcrowding?