I think what the mean is that reefsafe mean all corals and inverts are fine, but coral safe means you nice clean up crew or shrimp will be lunch. There are many fish out there that will not touch any corals, ie many puffers, large wrasse, and triggers, but put some fresh snails, shrimps or hermits in and watch the freeding frenzie. I have a large blueheaded wrasse and was so happy I scored this hermit crab deal, as I am putting them in the tank the wrasse is picking them off. So needless to say my tank is very close to nature as in the clean up crew only come out a night.