Different species - intelligent species - are what makes Fantasy fun for me too. Elves, Dwarves, Orcs... although Orc intelligence is debatable. The point is; here's a Mermaid. Or as I call her, Merdanser.
Originally I wasn't going to bother with a unique name and just say 'my version of a mermaid'. Further motivation for this developed when all I could come up with for a while was 'merlegs'. No Gnarlee, no. But merdanser is good. Hmm, perhaps I'll draw male versions in the future and call them Mermarchers. That sounds pretty good too.