With BTAs you might want to start off with some mysis (with the powerheads turned off). This is closer to their natural diet of zooplankton, as they don't tend to predate on fish as much as the carpet anemones, from what I've read.
You will, btw hear lots of contrary advice about feeding, which means there's more than one way of being successful. I feed mine infrequently and it's happy as larry. It is of course, not far under some 250W metal halides so don't take that to mean that's the best solution for you. In your case regular feeding with mysis is probably the best idea (it'll happy swallow a cube of frozen mysis). I wouldn't advise feeding it every day in a 50g, as you may start seeing water quality issues after a while.
I think you may be OK with your lighting, with a feeding regime of once every 2-3 days, but someone with experience of keeping them under PCs might want to chime in here...