I had a healthy Retic for over a year. Got him a couple ladies from TFD to keep him entertained. They were ALL dead within a month.
IF you are going to get them from TFD just be prepared for the worst. I'd have salt, enough heaters to hit 86 degrees, live blackworms, Prazi, Binox, and most of all a QT tank to keep them in for a minimum of a month, perferably 2.
My real beef with TFD wasn't really the rays that contaminated mine and died within a month, as they lasted longer then 80% of the rest of the fish I ordered, nor was it thier innability to read a tapemeasure. My main complaint was mis ID'd Payara. The only reason I ordered from them over other vendors was cheap Tats. I even called them to verify ID. They turned out to be Scombs that were half the advertised size, and in turn caused me to have to set up yet another tank so they weren't eaten.
They aren't a bad place to order from, they ARE cheap. Just NOT for beginners, you must be prepared for the worst, like fish that need work, won't eat, wrong size etc. Like mentioned QT's a must if you have existing stock.