I have a 55 gal. with plenty of Live fiji rock. I recently put 2 Arrow crabs in there assuming they would have enough room to safely coexist. I went to feed the tank today and noticed one crab had just stolen the other arrow crabs leg. Both arrows have their pinchers..one has 6 legs and the other has 5...it seems as if they have been at it before. Would you recommend taking one of the Arrows out or just let them grow back when they molt and they will stay out of each others way? \n \nI heard they can coexist but only if they have enough Rock to move around ...It was weird because I saw one of the arrows shoot half way across the tank only to tangle with the other and steal his leg- so it seems as if he had intentions of revenge.