I just adopted two of them myself. I'm looking forward to the transition towards marine (I had one years ago, but when I moved I could not take him with me) but I still have a few questions myself. Not trying to hijack your thread by any means, but maybe we can both learn a thing or two at the same time!
They start out Fresh, but increasingly Brackish is best as they grow, or so I've read. I didn't have my little guy very long, so I am unsure how quickly they grow.