Okay, one of the nifty things about mermaids is how many different versions there are in myths across the world; from things that are more like simian sharks to haunters of sacred wells.
This is also, of course, one of the most frustrating things about mermaids if you’re trying to put them in a well-constructed fantastic world, instead of local myths and legends. Do you have as many versions of mermaids as there are in folklore? Are they different in every port, like folklore? Are they like humans, having culture and cities? And how does that sort with the realities of intelligent species as we know them in this world – where you need a certain minimum number of people to create a civilization in the first place?
There is, however, a potential answer to this problem, if you poke some of Celtic folklore. Apparently at least some Scottish and Irish mermaids can take their tails off – like a dress! – to walk around on land like mostly-normal humans.
So… what if the differences between all the kinds of mermaids are like differences between various human cultures? Basically the same species, a little ethnic variation here and there… but the various tails, fins, claws or lack of same, etc., might all be different dresses. Culturally different tails you can take on and off, that might also provide other features.
Siren that drowns unwary sailors? One kind of dress. Koi sparkly mermaid that swims upriver to the water markets? Another kind of dress. Shark-toothed ship-wreckers that raid like water-breathing pirates? Yet another kind of dress – like getting kitted up as a Mongol raider instead of an elegant court lady.
If you did this, you could have your myriad mythical mermaids and still keep them as a more plausible fantastic species. Culture can create swarms of differences; the examples are all around here on Earth. And then you also get an interesting question: if the types of tails are cultural, who makes them?
Bonus? Your mermaids can swap their roles. The elegant court lady can doff her shimmering koi scales and pull on the swift reflexes and deadly striking speed of a swordfish, or tuna. Or turn dark assassin with the venomous spines and claws of a lionfish… or worse, a scorpionfish. If she’s in a mood.
Heaven help your heroes if she has a good friend who’s a sea-snake medusa!
Crossover Queen's Creative Chaos 
“I’ve got this weird cramp in my newest sharkfin.”
“Did you get it from a reputable dealer?”
“I got it from Uncle Finster Finest Fins.”
“Well it sounds like ‘Uncle Finster’ sold you a lemon.”
“Aww, really? But he was so nice!”
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“Did you hear about the latest food craze from the land lubbers?”
“What?”
“Shark Fin soup.”
“…are you saying they’re making *soup* from our old underwear!?”
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On Sirens, they’re actually one of my favorite mythology creatures but also one of the most frustrating because the original Greek ones were Birdlike. They always get confused with Mermaids just like Hades and Satan.
They do live on cliffs by the water so I always imagine some combination of sea glass and feather jewelry or some human made jewelry handed over by bewitched merchants. Which leaves a lot of room for different cloth as well. Maybe a certain clan that lives near the Aegean sea uses obsidian from Mt. Santorini.
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I’ve used the “sirens are bird-like” thing to give alternatives to harpies– ended up having the woman-headed bird type as harpies, and sirens as more Archaeopteryx looking humanoid design.
(Family D&D)
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That does sound very cool 😎. The Witcher 3 video game did something interesting with their Sirens making them more mermaid like but still having functional wings
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If bringing variants from video games into things, then the Dominions series games did Sirens as shifting between a mermaid-like form and a harpy-like form. Separate from having both mermaids and harpies, that is. And in that series, it was because they were specialized magic-wielders who purposely took took those forms for the sake of being able to lure targets in, or to escape if it became necessary, in places where enemies couldn’t easily follow (escaping land enemies in the water, and water enemies on land, and either type by flying).
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:shudders at sea-snake ANYTHING:
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Well, that is kind of the point… 😉
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Oh I didn’t need the image of a Koi inspired mermaid!! I have a book where there are different types depending on where the live along different coast lines and now I wanna do an oriental style….
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DeviantArt search koi mermaid. You will find pics. 🙂
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😍😍😍 so many cool images! Both Japanese and Chinese styles to, awesome
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*G* Yes!
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This is an interesting idea. Too often we just think of mermaids as having the bottom half of fish, but never give any thought as to which fish.
I’m imagining laborers dressing in octopus tentacles (kind of like Ursula in the Disney movie) to allow them to manipulate things easier, stealth hunters using shark tails so they can breach, or using dolphin tails to go faster. Koi tails would be like fancy dress…
The possibilities are endless!
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I am now thinking of Seanan McGuire’s horrifying “will definitely eat you or feed you to their much bigger girlfriend” mermaids in Rolling in the Deep/Into the Drowning Deep. (I was only able to skim the novelette because of the entire “yup they all gonna die” vibes.)
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Seems also obvious that this could be extended to culture specific versions of werewolves/shifters, vampires, witches, etc.
Now I’m noodling, again, at transposing some of the isekai generic fantasy stuff into interstellar settings. (I tend to be all ‘a society that builds spaceships might be very different from one that delves dungeons’ with a bit of ‘Oooh, supers’.)
It is an excuse for profound cultural differences, /and/ cute monster girls.
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Werewolf belts of shapeshifting are a thing, as are bear shirts and wolf cloaks.
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Yuup.
I was thinking selkies most strongly.
Also, about relative costs of clothing garments, then and now.
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I’ve been thinking lately about Star Wars. Mainly, the original movie in the original context.
The implied world building with Luke’s childhood is actually pretty cool. The line about whomp rats, and begger’s canyon. The later material that explained this said that he and his buddies had an actual aircraft, with an aircraft mounted weapon, that they used for this.
So, he and his friends were basically American farm kids, but had access to the stuff to repair and maintain such an aircraft for recreational purposes. (Well, it is possible that whomp rats are a pest if not hunted down.) One explanation, is that there is a lot of outdated but usable military equipment floating around after ‘the clone wars’. Another, is that the setting always tends to have that kind of stuff floating around, and accessible to interested teens.
Second, Luke was doing that sort of stuff, Uncle Lars had raised him up, and was still able to guide and command him. In the nineteen seventies, there were a lot of men living peacefully raising teenagers, who had seen serious stuff during the war, and were pretty chill about stuff. Lars and Beru were kind of mundanely awesome.
I’ve been finding those implied story choices kinda neat.
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Oh wow you have perfect timing!
I just got done rereading a WEBTOON called Strawberry Seafoam that’s sailor moon meets little mermaid. With the main character having different transformations depending on what she wants to do; shark for speed, dolphin for physical attack, and I think the jellyfish was the caster role…
And now I’m imagining modern-day mermaids getting their hands on bedazzlers and going to town on their koi tails!
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