I like dainichi color fx. Everyone else is gonna jump in and talk about NLS, too, but I don't like the baby pellets and I cannot seem to find any larger.
i bet if you just kept feeding those small pellets they'll become interested soon enough. I've had the same experience with large haps not eating the 2mm pellets, thought they were blind when pellets would rain on there head and they just ignore them. They came around, but i also went and brought the 3mm sinking pellets and 4.5 floating pellets,
Massivore
Gold
both made by hikari
along with hikari bloodworms
hikari silver sliders
hikari krill
hikari everything lol
i am hikari fan boy.
for african cichlids i would use hikari excel