When I was a little girl in the 90's, I had a little foam thing, and in it I stuck some mermaids. They had white tails. Stupidly, I had a weird thought come through my head as a kid and I flushed one down the toilet. There was a baby, a mom and I think another child. I do not remember there being a pet with them, but instead another baby. Might be wrong though, this was so many years ago.
It's pretty similar to the mermaid dolls in this thread.
They are called 'See Wees' or 'Tropigals' by Kenner.
But these came out in the 70's, and don't look to have been released again in the 90's :/
I remember having the two mermaid dolls in this picture.
I do not remember the pet at all. I'm sure a mermaid I had flushed down the toilet and not a pet.
My dolls came with a foam base like this
I do not remember a comb with mine at all.
More pictures of some of the series