I would have a LOT of fish in there. Large tangs for sure and many of them. Lots of angelfish. Several triggers (mostly Rhinecanthus but also niger, pinktail, and a couple crosshatch if I could find them for under $500 of course). I'd add 2-3 Arothron puffers, probably guinea fowl and golden. Dozens of wrasses of all shapes and sizes, though I'd stick with "reef safe" varieties. Mostly fairies. Lots of gobies and blennies. Several hawkfish! I think a small group of semilarvatus butterflies would complete the stocking list.