Cuckoo Catfish Synodontis multipunctatus/ S. grandiops

Cuckoo Catfish is a name given to several species of similar-looking spotted catfish native to deep waters of Lake Tanganyika (including the 2 shown plus the (False) Cuckoo Catfish which are occasional egg scatterers). Highly unusual for vertebrates outside of the bird world, these species are brood parasites. In the case of multipunctatus, at least (and maybe the others), the chosen host is a mouth-brooding cichlid. As she lays her eggs and they are fertilised, the catfish pair rush in to lay and fertilise their own on the same spot so that they are also scooped up by the mouth-brooding cichlid. The catfish eggs develop faster and their fry prey on the newly-hatched cichlids.