Royal Gramma Died

Well I decided to try a royal gramma on Tuesday. The fished looked to be doing very good at my LFS. I brought the fish home and dripped him for an hour or a little over. I put him in the tank and he went right to the bottom against a rock. I figured he was hiding. after about 10 minutes he was up swimming in a corner of the tank and found a hole in a rock. He laid in the hole for most part of the day but would come out to feed in front of his hole. He was eating and seemed to be doing good. Today, I woke up and I could see his face in the hole except he was dead. I seen a blue legged hermit eating his tail. Could it have been a hermit that grabbed him while he was sitting still or do you think stress could have been a factor? I have a 40 gallon breeder and only 2 ocellaris clowns and a skunk cleaner shrimp. Oh and 5 hermits