Large Crab Biting Small Crab's Shell

[Lephantome92]

I've had two medium PPs (Lief and Snorlax) for a bit, and just introduced some new ones, a small (Jacques) and another medium (still deciding the name). When I introduced the new ones, the old ones knocked antennae with the new medium and went on their way. Snorlax did similarly with Jacques, but Lief just doesn't seem to want to leave Jacques alone. L was constantly pinching J's shell and eating something. It didn't resemble any sort of attack, but they're still separate for now. Is this just normal behavior? Here is a video showing what I mean. L is to the right, J is either petrified or just chilling on his back

[Hermias_mom]

Looks like he's eating the calcium deposits off the shell. I've seen my crabs do this to empty shells. Don't know if it's calcium or some other white gunk, but some crabs like to eat it. Maybe give them some different types of calcium choices in the tat. (crushed up cuttlebone, eggshells, boiled/baked exoskeleton from seafood with no preservatives, oyster shell powder, etc.) Doesn't look agressive or like it's a problem to me, but I'm a pretty new crabber, lets see what others say.

[GotButterflies]

Did you dip the new guys into the freshwater of the crabitat?

[Lephantome92]

Did you dip the new guys into the freshwater of the crabitat?

No I'm guessing it was just as Hermias_mom suggested, because now they're playing nice. Jacques is by the food, and Leif is climbing on the new toy

In other news, within a few hours of being in his new home, the unnamed one thankfully switched out of his broken shell (You could see the back of his abdomen) and into a nice one!

[GotButterflies]

Did you dip the new guys into the freshwater of the crabitat?

No I'm guessing it was just as Hermias_mom suggested, because now they're playing nice. Jacques is by the food, and Leif is climbing on the new toy

In other news, within a few hours of being in his new home, the unnamed one thankfully switched out of his broken shell (You could see the back of his abdomen) and into a nice one!

Then that is what it was. The new guy smelled different, and your older guy picked up on it. Whenever you add new guys to the crabitat you need to dip them into the crabitat so that they smell like the crabitat and not like an intruder. Glad nothing bad came of it! Also glad he changed shells.