I purchased a pair that was supposedly eating everything, and turned out that only the female was actually eating. The male would pace all over the tank but not eat anything. I tried everything anyone recommended, funny thing I got so desparate I threw in some floating pellets and he actually ate them. He was a weird fish though. Later I moved on to freeze dried mysis (surface food) and then to semi-frozen SFkrill (look like salad shrimp to me) - I used a garlic product called entice, can't say it added anything to the process.
Things my Xhatch never touched - anything that sank quickly (including live feeder shrimp), live brine, frozen brine, hikari mysis (preferred full chunks of PE mysis) flake of any description.
My male passed away Xmas day, I got him July 1 and he took a month to eat. I don't know exactly why he passed away (not from wasting away), but as I said, he was "off". The female is doing fine, eats from anywhere in the water column.
Mark