yellow labs and hongi will eat them no probs mine eat fishy things (salmon/mussels/prawns ect very happily along with veg's and dried foods and frozen well anything really lol
Most of the labidochromis species will be fine eating other fish. I also believe there a few Melanochromis species that are fry predators as well. Although I wouldnt feed them only a fish diet. They are onmivores.