The gonads are the organs that produce sex cells.
Male fishes usually have paired testes that produce sperm. Females usually have paired ovaries that produce eggs.
The method by which the eggs and sperm meet varies widely among fishes. Many species are broadcast spawners, shedding their eggs and sperm into the water to fertilise external to the body. Others such as sharks and rays have internal fertilisation where the sperm are released into the body of the female.
Mark McGrouther , Collection Manager, Ichthyology