I suppose that it would be classified as a marine mammal which tend to be a bit divisive,re nomming them.
We were on a beach in Wales when we spotted a pod of dolphins having a bit of ‘sport’ with a small porpoise, which, in the end, washed up near to us, battered and quite dead.
My dad was quite disgusted with me, then a marine biologist, for suggesting we get the barbecue out and have a sample.
I mean, when else would you get a chance to try one totally guilt free?
So for me, it depends on how one acquires said mythological fish-lady.