wow... The colours for this piece, as few as they are, give such depth simply by the way you've composed it all. I think, save for the coral/seaweed being indicated in the piece, I love the way the scales turned out for her tail. It's lovely.
Oh god this is so pretty... OMG... I haven't been on dA in ages so I haven't been keeping up with ANYBODY and omg this is so pretty I think I'm going to go cry now. ;w; But really, I think one of the things that makes this successful is the high contrast in color combined with a more subtle contrast in value, and overall it has a lovely composition. And the way you handle the watercolor to get that beautiful light stain of red around her without letting it overpower the blue... yeah. Just awesome.