When I was a little girl, The Little Mermaid was my all time fave Disney film! I found a gorgeous mermaid pattern in Simply Crochet - Issue 32 that I just had to try.
For the tail I used 3 strands (blue, blue sparkle and green), then the body is two strands of skin tone, using a 4.5mm hook. I have played around with varying lengths of fringe for the hair, in red, orange and pink, for a luxurious 'Ariel-esque' look :)
For another look, I used a blue, green colour combo for the hair.
I like using multiple threads (or a chunky wool) for my amigurumi, so its big and cuddly :)
One issue that has come up, is that the neck on this pattern is quite flimsy, so with the weight of the hair, the head tends to flop over. I usually stuff pretty tight, so that the shape is kept, but Ive seen other people use anything from wooden sticks to wiring for support. Ive started playing around with flower wires in recent projects, so will let you know how I get one with them!