You don't think that some day that fang tooth will turn?I personally keep a 36" zebra (Gymnomuraena zebra) in my 8' 240 gallon, and it is a perfect fish. Doesn't bother anyone, completely ignores the damsels, dottyback, and hawkfish.
I also recently added a 22" white eye moray (Gymnothorax thyrsoideus) to the same system and so far, it has been the same. The previous owner had it with a variety of small fish for over 2 years and had zero fish disappear. Seems to primarily feed on octopus in the wild, mine happily eats squid, octopus, shrimp, and clam on the half shell, even eats jumbo mysis off the substrate if the fish don't get it before it hits the bottom. Also ignores any small fish, even gets driven out of the one rock pile periodically by the 3" neon dottyback. They usually top out at 18" or so in captivity, but can reach as long as 26".