Why some male fish fertilize eggs in their male relative’s nests

Researchers from the Karl-Franzens-Universität Graz in Austria may have discovered the explanation behind a seemingly counterintuitive act of cuckoldry that occurs in the animal kingdom, particularly among cichlid fish. Cuckoldry describes how some male cichlid fish mate with socially paired up females and end up fertilizing eggs in another male’s nest. This results in paternity … Read more


Talking about Fish reproduction in biology Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads … Read more

43.2A: External and Internal Fertilization

43.2A: External and Internal Fertilization Page ID 14119 Compare and contrast external and internal methods of fertilization External Fertilization External fertilization usually occurs in aquatic environments where both eggs and sperm are released into the water. After the sperm reaches the egg, fertilization can then take place. Most external fertilization happens during the process of … Read more

Fish fertilize eggs in their male relatives’ nests

Fish fertilize eggs in their male relatives’ nests Male cichlid fish sometimes fertilize eggs in nests belonging to one of their male relatives, a behaviour that is counter-intuitive yet ultimately beneficial, according to a study published in BMC Biology. Researchers at Karl-Franzens-Universität Graz, Austria, investigated the behaviour known as cuckoldry in cichlid fish, whereby ‘cuckolder’ … Read more

Female fish delivers offspring after eggs are fertilized inside of her

A team of researchers from the School of Life Sciences has discovered a stickleback fish that successfully delivered offspring from eggs that were fertilized while they were still inside of her. This represents the first-ever discovery of internal fertilization and the development of babies inside of a species that normally lays eggs. The experts collected … Read more


The production of marketable fish begins with the stocking of fry or juveniles into a rearing environment that assures optimum and rapid growth to allow harvest in the shortest possible time. The fish farmer has to obtain adequate number of young fish to meet his production goals. These fish can come from wild capture. However, … Read more