Russell's Piranha first appeared in Something Fishy as Russell's pet & show-and-tell subject.
Russell's Piranha (Serrasalminae) is a pet fish that first appeared in Something Fishy. A carnivorous creature, Russell's Piranha can devour animals wthin seconds, consuming both dead and live prey. It turns on its master when Lumpy places its fishbowl upside down on Russell's head, allowing the fish to consume all of the meat on Russell's head.
In Youtube Copyright School, Russell is seen juggling numerous piranhas while preparing to be launched from a cannon on his ship. However, he sneezes, causing him to lose focus and having both his arms bitten by piranhas. He is blasted through the ship, destroying it, leaving him in the water where the piranhas attack him.