My clowns will eat almost anything, but I have had some fish that would love all frozen, but hated pellet, loved flake and some fish the other way around. Go figure. Each has their own preference. Maybe they will begin to adapt when bit older.
By the way, my percula pair were hilarious today. My female (larger - over 1.5yrs) and my male (baby - 8months) have been together now4 months. She was actually pushing him to the sand with her nose and steering him around. He then got up and followed her around again. Strange fish, but they are happy. Yours should establish female/male soon enough. By the pic they are the same size, so it could be a bit more duking it out for a while.