I've had experiences where newer clownfish wouldn't eat any frozen food that had a gelatin-like binder and pretty much stayed cube-like. For whatever reason, pellets are the last food I'm typically able to get any new fish to eat. My go-to's are always frozen PE mysis (I thaw, then strain, then for smaller fish, mush the shrimp up into smaller pieces) and flake. Some fish can take forever to accept pellets, especially if they've never seen them before, which is entirely possible.
If I had to suggest a combo that'll almost certainly get them to eat, I'd say PE frozen mysis, PE flake (just came out and is primary made of mysis), and possibly frozen blood worms (also thawed, strained, and broken up). Soaking frozen with a garlic additive may help too, since many believe garlic will entice their appetite. With any new fish, I like to feed heavily the first week and keep offering different types of food until I find something they'll readily accept, then ween them onto the other stuff.