If you asked the typical human of the year 2516 what humanity's greatest achievement was, they would probably answer "the terraforming of Venus." Not only had the planet's atmosphere been altered, but it had been moved into a new orbit farther away from the sun to make it cool enough for humans to inhabit.
Now nine tenths of the planet was covered by ocean. Humanity had befouled the oceans of earth to the point where the most optimistic estimates were that they would take centuries to heal, but the new ocean on Venus was clean and stocked with what remained of earthly oceanic fauna and flora, or what could be recovered from DNA. The invention of bulk teleportation had made Venusian fish, clean and delicious, a staple of the diet of most humans.
The oceans were kept clean, and the fisheries managed, by humans that had been adapted to live under the sea. These took a variety of forms, including whale and squid-based forms, but the most basic and by far the most numerous were the classical merfolk. Since she was a little girl, Monica had fantasized about joining them. Once she reached puberty, she found merfolk of both sexes sexy. (Like 70% of earth's population, Monica was bisexual. She had always found Ashley's strict heterosexuality weird.) But the challenges of getting the new form (even though the fishery would pay for it in exchange for a labor contract) and pulling up stakes and moving to Venus had always seemed too great. But if Ashley could totally remake, well, she guessed it was his life now, why couldn't she?
And so Monica found herself talking to a merfolk recruiter.