FWIW, one way to solve this problem would be to postulate mermaids to be marine mammals (they do have a placental umbilicus and mammaries after all in most depictions...), so their bottom part would be more akin to that of a dolphin, not a fish.
FWIW, one way to solve this problem would be to postulate mermaids to be marine mammals (they do have a placental umbilicus and mammaries after all in most depictions...), so their bottom part would be more akin to that of a dolphin, not a fish.