Zebra/dwarf blue legged hermits

Question. I currently have two tanks. I just started a new one a few weeks ago, an innovative marine 16 gallon. I bought some snails and two zebra legged and 4 dwarf. The past few days, I woke up to all of my snails being dead and eaten. Now, I know it could only be two things: the hermits or a mantis. I have not heard any "popping" in the tank (although I have two pistols in the tank next to it and could have misheard) at all. My question is, would these types of hermits eat snails and not move into their shells? I have the same in my other tank with a ton of snails and they all seem to be just fine.

 

I have not found this type to be overly aggressive.

When snail die, usually it's swings in SG/pH and or starvation.

I would check those first.

 

They will definitely eat sick/dying/dead snails. However, IME, once a hermit develops a taste for snail meat, they will actively hunt them down just to eat them as opposed to eating them for their shells. Lots of SH keepers report the same behavior from the blue legs and zebras, and I've seen them latch onto resting SH's tails as well.

About the safest hermits you can get are the scarlet reef hermits (Paguristes cadenati), which are red with yellow eyestalks. These are about as docile as hermits come, and are the only ones we will keep these days.