They're pretty small. The size of a quarter. So how long do you think they can go without eatingUnless they're in really poor shape I wouldn't fret just yet. You say young, how large are they?
In my experience if young datnoids don't take to pellets or frozen foods early on I've had pretty good success using live tubifex worms and transitioning into frozen shrimp/fillet/pellets from there.
Coming up to the surface is a good sign, be patient, they sound ready to take something it's just a matter of one pulling the trigger and the others will lilely follow. From there competition for food should encourage more enthusiastic eating.
Welcome aboardThey're pretty small. The size of a quarter. So how long do you think they can go without eating