The trick is finding one that is captive bread and raised from ORA, BIOTA, etc. Even if you don't see them eat frozen and flakes right away, you always supplement with Pods for the 1st 3 months, then eventually they will start thriving.
Trust me, I know all the myths and mystery surrounding these fish, and I always wanted one but never got one.
Fast Forward to last December and my nephew set up his 13.5 Evo Tank, 3 months later, after adding his black Ice Clown, he added a Mandarin Dragonett, I told him not to, but he absolutely wanted one...so he got one from one of our local LFS who pretty much guaranteed his survival...
Another LFS told us they were wild caught, and couldn't guarantee it's survival unless you had a super mature tank with tons of pod growth.
We supplement with Pods for 1st 3 months, and now, we haven't dosed Pods in a while, dude is fat and happy and is almost twice the size he was originally.
Just find one that is absolutely captive bread. I want one now too, but my 40GB is stocked full, and I don't want him getting harassed by my Diamond Goby.