Emeralds crabs will get you people on both sides of the fence. My personal experience showed me that they are great if you have algae for them too eat. I started with 6 emeralds. 4 males and 2 females. After my hair algae was no more, some of the males started to go after the odd coral. I sold the 4 males and kept the 2 females. Algae is what they like most. No algae, well, then you will likely have some problems. They will not let themselves starve to death. But that is no different than hermit crabs or any other crab for that matter. I agree that the larger male emerald crabs eat alot and will be the first ones to go after your snails or corals. I never had trouble with the females. Snails are a safe bet. I don't regret getting the emeralds, they add more character to the tank. I would recommend only getting a few for your tank. That should be pretty safe for a 110 gallon tank.