mysis is alot better then brine and often gets a better feeding response. What size tank and what other fish do you have.... after a week there is no reason they are still hiding unless something is making them hide, lyretails aren't really shy fish.
They are really more shy when I come around. If I stay far away they don't seem to care. As soon as I get close they swim back under some rocks. What I have actually started doing is I kind of low crawl to the tank to feed and they have been staying out a little more. I have a 90 gallon with, yellow tang, kole tang, paired maroon clowns, 6 line, and a rusty wrasse, brown benny, diamond goby, some cleaner shrimp, and peppermints, snails and blue leg hermits. none of the fish have been aggressive towards them
the male is eating just fine now. I haven't seen the female eat yet but she doesn't look thin. No harassing is going on that i can see. not marks or bite marks on her fins. Still hides a fare amount. Comes out every now and then, but if I come around she normally goes back to her hiding place. They have been in the tank for about two weeks now. I would like if she wasn't eating I would see some kind of sign...thin looking or something.
She is really one of the larger fish in the tank around 4 inches I would say. I'll just keep doing what i'm doing and hope she gets a little more brave.