Well, I asked my daughter what she wanted to be, expecting yet another kittycat costume...and she surprised me!
"Blue mermaid, mom...NOT ARIEL!"
Well, cool, I wasn't interested in knocking off Disney anyway!

Its all handmade except the wig base and fishy necklaces:

Love that swishy tail! There's a ton of flexi boning in it.

The 'seaweed' is ribbon and yarn with little shells I cut out of mylar:

She is very very happy...so am I!