Sneaking is common in nest-building fish with paternal care, but the role of nest-opening size in protecting against entry by sneaker males has never been tested before. Using the sand goby (Pomatoschistus minutus), a fish with exclusive paternal care, experimental manipulations of nest openings...

To test if an increased sperm competition risk affects male behavior and mating decisions of both sexes, we performed two experiments using the sand goby, Pomatoschistus minutus, a nest-building fish with exclusive paternal care. In our first experiment, a nest-holding male, with a confined...

In fish, brood cycling parental males sometimes eat some or all of their eggs, a behavior termed filial cannibalism. We tested predictions of filial cannibalism models related to the cost of parental care in the male sand goby, Pomatoschistus minutus, by increasing the parental effort (fanning...