They don't do well in captivity. They typically won't eat and will starve within a month. On the rare occasion, one will survive but two years is about the max. They have been known to live longer when kept in pairs (if you can get two to eat).
In the wild, they live around 20 years.
Most online retailers typically show an amazingly beautiful blue and yellow adult male. But then they state that they'll ship you a juvenile (typical). Juveniles are pitch black.
I love eels but this is one that I think for the most part should probably be left in the ocean. I had luck keeping one quite a few years ago. Lived for just under 3 years. I had quite a bit of live rock in the tank and also had pvc pipe burried under the sand with a couple openings. They build there own burrows in the wild and this one did as well but also spent a lot of time in the pipe. As far as reef safe it depends what your thinking about having with it. They will eat shrimp and crabs. I used to feed mine ghost shrimp, guppies and mollies.