My mantis, almost always visible during the day, has started to put his telson, tail, at the front end of his entrance. he walks around the tank alot, a 72g, and isn't bothered by any of the fish. Except sometimes when the blenny is a bit territorital and gives the mantis a good whack in the face with his tail. Anyway, is it normal for them to block their entrance up with their tails?