I really love the way the fish move, I spent a lot of time in our own game working on how the tentacles moved around our game, and I think your fish are very much along a similar vein of very satisfying to watch on the screen and how they react to your mouse. Visually very appealing motion.
I sometimes felt like the camera bounced around a bit much as my fish spun, but maybe that's part of the challenge. Overall well done, really nice look to it.