is there a particular reason? even if it were only a 2 inch? perhaps just one of [THESE]?
What about a 2-4 inch sea urchin?
Is there a reason you believe it would starve?
I was also looking at orange turbo snails, sexy shrimp and the blue leg dwarf hermit crab. do you think 1 crab, 1-2 snails and 2-3 shrimp maybe would be ok?
Its a personal preference, i believe that nems should be in bigger tanks..The condy in that link grows a lot bigger than 2 - 4 inches, more like about 7 - 8 inches and they pack a very big sting aswell to anything that comes in its way when moving..