#okay this took a while but here it is
A curious anon asked whether there were also stories about mermen among the many stories about mermaids. There are many water creatures in folklore, including male ones. But many of them do not look half-fish, half-human, like we expect from mermaids. A “watery” or “fishy” looking human is actually more common. And it’s actually not uncommon to have fishtailed women and scaly-legged men spoken of as being direct counterparts in folklore. But there are some more mermaid-like mermen to be found.
As far as stories go, what we now think of as classic merfolk, seem to show up most in folklore from the British Isles and Western and Northern European coast. (But if you include deities the Babylonians, Syrians and Greeks definitely join the club.) While female merfolk are by far the most prevalent, here are the mermen I know of:
Icelandic stories speak of a “marbendil”, which is a merman that is only seen when accidentally fished up from the deep. One story describes him as having a big head and long arms, but resembling a seal from the waist down. The other as “a great fish with a mans’ head and body”. They were thought to have some sort of clairvoyance and could tell a person’s fortune, just like their female counterparts. They have homes and family at the bottom of the sea and keep sea-cattle.
On the Shetland Islands there are stories about a whole society of mar-folk that lived in the ocean, who looked fully human while in their homes or when they go ashore, but who traveled through the water by changing their bottom half to a fish tale. They were fond of music, a bit smaller than the average human, and the men in particular of a darker complexion, with dark or reddish hair. They too could tell fortunes. Some of the stories overlap with those about selkies.
In Norway they have a similar divide as the Shetland Islands, with both mermen and mermaids having fishtails, but the men a little darker than the women, with a long black beard and hair. They could foretell the future, but also bring misfortune. A friendly merman might warn fishermen about coming storms.
While the rarely mentioned “merrow-man” from Irish folklore seems to be ugly, but more man than fish, brief mentions of Welsh mermen give them both a fish tail and beautiful long hair. In tales from Cornwall the mention of “merrymen” are equally brief, though sometimes described as dangerous. They seem to exist mostly in reference to the mermaids, as their fathers or husbands.
In both the Netherlands and Germany there are several similar stories about a mermaid that was caught by fishermen, whose ship is immediately followed by a merman. He turns out to be her husband, and begs for her release. When they refuse, he curses their village and foretells that it will be completely destroyed by the sea. Another Dutch story tells of some sailors who accidentally wound a merman with long red hair and beard. They are so shocked to see him that they do not catch him, much to their helmsman’s dismay.
Lastly, there seems to be a pretty complex fishtailed merfolk society in one of the stories from Arabian Nights. And, while beyond Europe creatures that are half-water snake seem much more common than half-fish, one tale attributed to the Teton tribe from what is now Midwestern USA has a woman that flees into a river and becomes a fish from the waist downward.
