I really like the way the BC on this cake looks like water. Can anyone give me advice on how I could achieve this look? Thanks!

http://cakesbyanitha.blogspot.com/2008/11/mermaid-cake.html

I would use the back of a spoon. Put on a thickish coat of frosting in the lighter color but don't smooth it much. Using a darker color frosting, spread some over the lighter and swirl it around with the back of a spoon.

Just do a rustic icing with a spatula and add a little darker blue food coloring to the spatula in certain places. that will give you the mottled water look.

Thank you for your responses!