I had one for 10 years. He got 30". They are not likely to eat your fish, but there are exceptions. Among the morays, it is among your safest choices.
A GREAT fish, easy to keep and feed, very tame. At your SF's size, I'd feed him 5 days a week or so. He'll grow quickly. While I'm sure it is fun to hand-feed him, you will eventually not want to do it anymore. As someone said, they are as blind as Mr. Magoo, and I got bit a few times when he mistook my fingers for food. It hurt A LOT when he was over 2 ft. long, and I had a V-shaped bloody cut that took a long time to stop bleeding. I would compare it to squeezing your finger hard with a pair of steel pliers for 2 seconds. They get VERY strong jaws when they are older (they crushed shelled animals for a living, remember).