We had one, at my store, for close to 4 months. It was in a full blown 150gal. reef, 250lb rock, 3 x 250W MH, that had been established for over 3 years.
Tank mates were a Chocolate Tang, a school of Square Back Anthias, a pair of Blue Throat Triggers, a Lineatus Wrasse and a few others.
We got it in knowing their bad track record, for long term survival, but we were hopeful.
30 minutes out of the bag and it was eating everything from mysis to formula 1 and 2 and even sheets of nori.
4 months and going strong...then one day, dead.
I dont think they're a species that should be kept, no matter the maturity of the tank. Every person I've ever known, who's had one, has lost it...survival is usually 1 - 3 months.
They are absolutely spectacular looking fish. Every day I'd make the comment that I wish there was a Moray with the same coloration.