I have had them in my reef and they didn't bother my corals but if you do not provide larger shells for them to grow into they go for you snails that is to say if you have snails if you don't they might go after each other
Everyone is going to have their own opinion to this question, but from my experience I haven't had a huge problem with them. Now I am not saying they don't eat snails and each other....because they DO! I agree with porscheguy...do make sure you have bigger snails for them to move into. I learned the hard way by mine eating my snails to get a bigger shell. I added more snails and some extra empty shells and haven't really had a problem since! Good luck.
I prefer scarlet hermits because they are less aggressive and prettier.
If anything in the tank gets sick, a blue legged swarm will make it dissappear(lunch).
BurnNSpy
I agree. Blue hermits are OK in reef tank yet they can go after your snails. I even named one blue hermit carbs in my tank "snail exterminator". He knows how to get them and after them. Nobody's safe when he is around Yet, they are doing a good job cleaning up and are useful in a reef tank where you cannot move the rocks too much in the case something dies.