Hi guys. I'm new to saltwater aquariums and need a little help identifying a few fish. I recently was given a 55g established tank with live rock and 4 fish. 2 of the fish I recognize right away, one being a tomato clown and the other a volitans lionfish. The two I an having trouble properly identifying are a type of tang and a type of triggerfish. The tang looks exactly like a blue Caribbean except it is darker in color, almost black with some lighter greyish purple coloration around the fins and tail. It has the small mark at the base of the tail as well. The trigger is small and white and has sideways Chevron markings on the back half of the body. I will try to upload pictures in a bit