Small yellow goby, eating concerns

[The Guy]

I have 2 little yellow gobies they each hang out on a zoey coral on each end of the tank it seems to me that they don't go for the foods given. I do a variety of foods including mysis, brine, ocean plankton, small new spectum pellets and some flake so it's little different each day. Is it possible foods are too big for them or what? Can anyone suggest other foods that the little guys would go for? How about baby brine shrimp?
Help with this would be appreciated. Cheers Laurie