Cichlids can be very finicky eaters - they're worse than cats and toddlers!
When I ran out of the Ocean Nutrition flakes, my angels refused to eat anything else I offered them. I had to try offering them every food I had on hand until they settled on some Hikari FW
flake that I had won in a raffle.
Keep trying different foods you have until you hit on whatever they have a craving for. Just be careful not to put too much in, and keep up with the gravel vacs/PWCs.