I skipped through 'The Shape of Water' and I would say it's basically bestiality romanticized.let's say a porn video of a janitor with a lab monkey on the loose and now the monkey was replaced by a fishman and threw in some nostalgic shades and music. Well, it's said to be a retro-fantasy set in 60s' cold war era. The aspiring script writer inside me gave it a slight twist...mmm...how about setting it in the 2020s sino-yank econ cold war era: A janitor found a meaty cow size dog inside a secret installation and the chicoms wanted to steal it for meat dog genetic breeding experiment...
Your imagination for the rest of the story would be as good as mine...