How long have you had it?
Ive had ones that refused to eat for weeks, and I just got one yesterday that nearly ripped the tongs out of my hand while still in the acclimation bucket...
I have 3 right now, all eating frozen off tongs and feeding stick.
Yesterday I got what I hope is a male for my female, but theres no way I can tell.
Try feeding gutloaded ghostshrimp, once its eating them start using a feeding stick to give the ghostshrimp, then start using frozen things mixed in, start slow, trickery is key.
Once they figure out the stick/tongs mean food, they eat with enthusiasm.