My BGK has started only preferring pellets to frozen silverside too(She loves Hikari and Cichlid and even Tetra ones). And after being caught in the wild that seems odd to me.
It is great that he eats cichlid sticks, everything good for him in it.... my CK eats everything including algae pellets.. he claims all food and i have never seen him turn anything down, i have a job keeping all his tankmates fed.