I am a quarantine fanatic. I quarantine even my live rock and live sand to include GARF grunge. I have had some Gorilla crabs, no mantis shrimp yet. I have no problem getting rid of the crabs, as it is easy enough with a quarantine tank, but I hate macro algae on my rock, but I love everything good that comes with the rock that just doesn't come with rock that has sat on beaches and docks for a few days to a week or so before being shipped to California for trans shipping to retailers where it is some what resuscitated just to mainly provide some coraline algae and bacteria. I have photo graphs taken by a friend of divers lowering sledge hammers and metal pry bars into the ocean to get live rocks, and photos of piles of rock laying on beaches where maybe a couple times a day a child throws pails of water at the piles. I digress, I should have made some mention of the good possibility of bad hitch hikers also. At least there are hitch hiker though. But true with the many good can come some bad. Quarantining is a good thing, for every thing that is alive or for anything that comes with life forms that is to be added to a marine tank.
Thanks, lcstorc for bringing that up.