The genital papilla is a normally small tube extending from a fishes vent on the underside of the body which is used for depositing eggs or sperm in species which attach or deposit their eggs in a controlled manner. Fish such as Angelfish, or Oscars, can be sexed by the shape of the genital papilla when the fish are in breeding condition. In some fish, a pronounced appearance of the genital papilla can be an indication of spawning about to take place.