Kleptogamy refers to the sneaking behavior during reproduction. Females prefer male gobies with large bodies. Since not all males have large bodies, the smaller ones may cheat instead of expending energy to find mates. The sneakers wait near the spawning ground of paired fish. The sneakers then release their sperm on the spawning ground as soon as the paired female releases her eggs. Though sneakers’ sperm fertilizes some eggs, the paired male cannot distinguish the eggs fertilized by the sneakers from those fertilized by his own sperm. Therefore, the paired male gives parental care equally to all the eggs.