haha, i knew you guys would say that. It does look like an evil crab, i know the rock he hangs out on so if its time to take him out i'll know where to look. i'll research some more about them, but i got to tell you, crabs are one of my favorite creatures, so he'll stay for now. I dont have a sump, so i dont know what i would do with him. i dont want to kill him.
Speaking of which, my diamond goby sadly passed away over night. He hasnt been doing well lately i think because of my temperature fluctuations (he was doing fine and eating well before that). He was a really cool fish
Thanks for the tips Perfect Dark, it looks to be like my heater was the problem, its works fine now and the temp is at a stable 77 again but im going to get a replacement for peace of mind.