Great designed app-but slows down the computer a bit

I like this app a lot as it makes wallpape constantly changing with fish moving around. Overall I like. The only thing I feel need to be improved is that it slows down my computer.
After I downloaded and checked "automatic start" when turn on the computer, I feel it takes much longer period of time. I monitored the CPU usage and found this app used estimately 18%. Maybe I am so sensitive to the speed. Overall I like this app regarding the graphy design.

Nickname 4 fun about Koi Pond 3D