"It's important to have a job that makes a difference, boys. That's why I manually masturbate caged animals for artificial insemination." -- rando convenience store customer in Clerks, 1994
NOT FISH despite the name. Cephalopods are molluscs like snails! They are pretty smart and can have somewhat elaborate mating routines, and most species are somewhat careful about sperm sac delivery AFAIK. Lonely prisoners are not good behaviour models.