Cardinalfish (Cheilodipterus sp.) dads do their part to protect their eggs by gingerly carrying them in their mouths. However, the dads could easily swallow the whole bunch in one gulp! To keep her eggs alive, the cardinalfish mom will often lay a number of yolkless dummy eggs along with the real ones. These dummy eggs trick the dad into thinking he has more future offspring in his mouth -- and thus the clutch is worth careful protection.