Originally Posted by Dinogeorge
They are not mating, they are fighting. Tangs have two little “switchblades” at the base of their tails. They use them to inflict injuries into rivals or predators. Tangs are sometimes called surgeon fish because of their nasty ability to slash you open with their little knives.
So they are backing up and trying to slash the other guy with their tail.
Keep an eye on them in case they start to cut each other up.
Good luck man.
Wow, totally true. I didn't even think of that. That is dead on! I completely forgot about that!