GUPPY GONOPODIUMS

Most fish just dump their eggs and sperm and hope for the best.  Guppies are one of the few fish where males have a penis to internally fertilize females.  The structure is called a “gonopodium” because it is a modified fin that functions as a sperm delivery tool (aka penis).  A male’s gonopodium may be up to 1/3 the body length.  The males flash their gonopodium at the females during courtship.  Regrettably, while they are flashing their gonopodium, they are … distracted and easy prey for other fish.  While some guppies may escape predation, the large membered individuals are slower and more likely to get eaten (insert the giggle of a teenage boy here).  So, while a bigger gonopodium may be flashy, a more reasonably sized gonopodium may be safer.