This has been driving me mad since I remembered it. When I was just a kid - in the 1980s - I came across this black-and-white comic in the grocery store newsstand. I can't recall if it was part of a larger comic compilation or horror magazine, but I remember the gist of the story.
Basically, it's about a group of people who accidentally catch a mermaid. They hook what they think is a swimming woman, but the fish tail is sort of a giveaway. They realize that there are a lot of others, and they all have rather sharp, carnivorous teeth. So of course they haul the one they hooked into the boat. She winds up in an aquarium, blah blah blah. One of the guys thinks it'll be a good idea to swim with her, she tenderly embraces him...and drowns him. That's most of what I recall - I think they released her after that, realizing she was too dangerous to keep around.
I've been looking ALL OVER for this comic. No matter what I plug into Google, I can't seem to catch a lead on this thing. Hopefully someone out ther knows what I'm talking about!