It's hard to see it but I did brush the bottom half of the cake in blue petal dust to create the illusion of depth since the ocean does get darker the deeper you go -it's like a subtle Ombre effect. I also made the splashes around the tail fin by ruffling up some circles of fondant, lightly folding it in half then brushing the tips with white royal icing (brush embroidery method). I then dusted some white glitter along the tips of the fin and water splashes and added pearl dust around some of the decorations. The bubbles were painted on really lightly with white gel color diluted with vodka and the cutter used on the name were FMM Upper Case Tappit Cutters.
All the decorations were made using Wilton Fondant. Wilton Fondant dries up quickly but, it also gives you time to work with it - it's similar to mixing together fondant and gumpaste. I have been liking how easy it is to work with. I do still like covering my cakes with Marshmallow Fondant (click for my recipe) since, in my opinion, it tastes yummy and covers up cakes wonderfully.
I must have watched, The Little Mermaid over a million times when it first came out on VHS ages ago and one of my favorite characters is Sebastian and his songs; love his personality. Therefore, to pay homage to Sebastian (the little red, crab), I modeled him singing to Ariel in his catchy, big, deep voice, "♪...Under the sea, Under the sea, Darling its better down where its wetter, take it from me...♪"
The little mermaid is a signature look I have developed over the past few years in designing Princesses and different character themed cookies, cake decorations, and cupcake toppers. She looks so perfect on this cake. I also wanted to try something uniquely different with her and designed the mermaids tail fin to stick out over the top of the cake. The inspiration was drawn from a scuba diver cake I saw where his swimming fins were sticking out the same way. I thought this same concept would look really cool in a fish-tail form and my 3-year old niece loved it!
Update: It's been really neat seeing everyone's version of this cake being made and how popular it has become. Thank you!