yeah, shrimps and crabs are a gamble....I've "removed" several problem hitchhiker crabs after catching them in the act of feasting on my polyps, I take care of hitchiker crabs on sight now...
I've had problems with blueleg hermits as well....they are no longer members of my tank. I've introduced peppermint shrimps to my reef to control aptasia, only to have them dine on my yellow polyps, they are also no longer welcome inhabitants in my reef.
The only crabs I presently have in my tank (that I'm aware of, I always seem to find the odd hitchhiker every 6 months or so) are 3 scarlet reef hermits. They have been in my tank for about 3 years now, and I have not witnessed any problems from them, but as soon as I even suspect they are becoming problematic, they will be removed as well.
MikeS
I've had problems with blueleg hermits as well....they are no longer members of my tank. I've introduced peppermint shrimps to my reef to control aptasia, only to have them dine on my yellow polyps, they are also no longer welcome inhabitants in my reef.
The only crabs I presently have in my tank (that I'm aware of, I always seem to find the odd hitchhiker every 6 months or so) are 3 scarlet reef hermits. They have been in my tank for about 3 years now, and I have not witnessed any problems from them, but as soon as I even suspect they are becoming problematic, they will be removed as well.
MikeS