emarld crab safe?

[marlin]

in my 12g nano which has been up and running well for over a year, i added a emarld crab about 1-1 1/2 weeks ago since then ivenot seen my 2peppermint shrimps, arrow crab, or cleaner shrimp, any suggestons on what happened, i dont want to make this same mistae once my 75 is complete.

 

[miamireefr]

I have 4 emeralds in my 46 and have been there for months with no sign of dead anything except an occasional stand off from a hermit which lasts about 5 seconds or now a stand off with my goby. Never seen them even go after my cleaner. Make sure to supply with some algae at least 1-2 times a week if he doesn't have any....of course i am no expert but this has worked for me.