Listen, we still don't know how eels reproduce. Our knowledge has never been all inclusive and properly disseminated. The fearful cave-dwelling scribes who wrote the old testament were clearly not up to date on their biology.
https://www.newyorker.com/magazine/2020/05/25/where-do-eels-...
This isn’t even the only weird idea that people used to have about reproduction; there’s also stuff like https://en.wikipedia.org/wiki/Barnacle_goose_myth