Coral Banded Shrimp Problem

Hey guys so I have a bit of an emergency here. I recently bought a Coral Banded Shrimp and he has been in the tank for about 3 days now and I came home from work today to see that both of his arms have been broken off (you know those real long main arms). I understand that they grow back but I am wondering as to why this might have happened. I currently only have about 10 red legged hermit crabs, 2 blue legged hermits, a osicilian clown fish and a engineer goby (about 5 inches long). Do you guys know what could have caused this suddenly?

I have one theory. I sank a cube of brine shrimp in a clip directly in front of the gobys cave. I think the coral banded shrimp was hanging from above and trying to mow down on some shrimp then accidentally got his arms nicked off by the goby out of the cave.

Do you guys have any theories and what I should do in the future?



Thanks guys!