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Predation can play an important role in the evolution and maintenance of prey colour polymorphisms. Several factors are known to affect predator choice, including the prey's relative abundance and conspicuousness. In polymorphic prey species, predators often target the most common or most visible morphs. To test if predator choice can explain why in Midas cichlid fish the more visible (gold) morph is also more rare than the inconspicuous dark morph, we conducted predation experiments using two differently coloured wax models in Nicaraguan crater lakes. Contrary to expectations, we observed an overall higher attack rate on the much more abundant, yet less conspicuous dark models, and propose frequency-dependent predation as a potential explanation for this result. Interestingly, the attack rate differed between different types of predators. While avian predators were biased towards the abundant and …