Help! I'm a Fish

Help! I'm a Fish, also known A Fish Tale, is a 2000 Danish animated movie.
Plot.
A 12 or 13 year old boy nicknamed Fly wants to go fishing. His parents tell him that they are going out and that his aunt Anna will babysit him and his little sister Stella. Fly’s cousin Chuck, who loves computers and science, comes with her. When Anna takes a nap, Fly and Stella sneak out to go fishing. Chuck follows them. They meet a mad scientist named Professor MacKrill. MacKrill is scared of global warming. Because of this, he created a potion to turn humans into fish. He also created an antidote for the potion. Stella becomes thirsty, drinks the potion and turns into a starfish, She then gets lost in the ocean. Fly drinks the potion and turns into a California flying fish so he can look for her. Chuck does not know how to swim so he drinks the potion. It turns him into a jellyfish. MacKrill warns him that if they do not drink the antidote in the next two days then they will stay fish for the rest of their lives. 
A Great White Shark and pilot fish accidentally drink part of the antidote. This gives them human intelligence. The pilot fish names himself Joe and creates a civilization of talking fish with himself as the leader. After Fly tries to steal the antidote from him, Joe has Fly, Chuck and Stella locked up but they escape. They find what they need to create the antidote but Joe steals it from them after his shark wounds Fly. Chuck then takes Fly and Stella to McKrill’s pipes to flood his laboratory and take the antidote. Joe follows them and steals it to make himself smarter. Fly calls Joe stupid. When Joe tells Fly that he can kill him, Fly tells him that any idiot can do that. He asks Joe many trivia questions about mathematics, special relativity and philosophy. When Joe does not know the answers, he drinks the antidote to figure them out. He drinks enough of the antidote that he becomes human and drowns. Fly, Chuck and Stella get the antidote and become human again. Chuck thinks Fly is dead but it turns out he is alive and just has a broken leg. Chuck learns to swim and Fly starts being interested in computers and science. Stella gets a seahorse, Sasha, as a pet.
Reception.
The movie won the Children’s Jury Award at the Chicago International Children’s Film Festival but it did not do well with sales. It cost $18 million to make and only made $5.6 million dollars.