If you mean very realistic, then no.
But if you want a fun fishie screensaver that gives you the opportunity to puff infinite pufferfish, then look no further than the screensaver I made which you can download here
And don't forget to move your mouse over the puffers!
i have a pretty realistic aquarium screen saver. my brother bought it from fry's for like 10 bucks, but it came with a $10 rebate so it was practically free! i think its called serenescreen or something. you can download a demo version of it online. its something like SereneScreen Marine Aquarium. just google it or something.