At least two My Pretty Mermaids playsets were made. They include:

Playset #1- Bedroom Set

-purple base with yellow treasure chest (Pictured Below)
- a "water bed mattress" which was a little plastic piece that you could fill with water and inside it had little sparkles
and flat plastic starfishes and fish that moved around inside the water part of the bed - a hot pink felt pillow
-a hot pink felt blanket with a blue heart in the bottom right corner (I think it was a heart)
- a flat, felt, merbear it was blue with hot pink and white paint and it had a tail fin similar to the mpm because it had a pink star on its tail fin
- and a comb, (it might have been the plastic rainbow with the star on the end one)
The bottom of the base reads Item #1612 1991 Playskool INC

Playset #2- Bathtub

- huge purple almost seashell shaped tub with a aqua towel rack and a fake mirror attached to it
- a pink (terry cloth) towel with a purple starfish on the bottom right corner
- a little fish that if you filled it with water you could squirt it out its mouth, and it also changed colors in hot and cold water, it went from pink to purple (or might be the other way around)
- a chunky yellow barette with a strand of fake purple hair coming out of it
- a seahorse shaped comb (I think it was aqua) (Pictured Below)
Thanks to Foxtale for the information!