Fritz was a homeless big black terrier, who went on Titanic, and became a leader and protector of most of it's animals, except for Gertrude's cat, Geoffrey, and Corynthia's Chihuahua, Tiger, who became outcasts friends and partners actively opposing the rest of animals, and constantly menacing mice, especially Maxie and his parents, as Geoffrey wanted to eat them, and Tiger helped him. Fritz and other animals disliked the two. Fritz protected mice from them, and often attacked and chased them instead. When Maxie was attacked by them in cargo hold, Fritz saved him, and chased them away. Maxie thanked him for saving him, saying “If it hadn’t been for you, I would be now in someone else’s digestion.” Fritz introduced himself to him, gently scolded him, said that he shouldn’t wander off without consulting him as he's in charge, and started singing, "Party Time", about party and how he’s their leader and protector. Then Fritz tells them that if they're going to party, they need food and drinks. Fritz went on a deck, met with Kate, her mate and Flopsy and asked them for help. He told them about party, and asked for help with food and drinks. He also told them about Geoffrey, and Tiger, calling them a "pair of weirdos", and Geoffrey "a psycho redhaired cat", and Tiger "someone he hesitate to call one of them" and that he's "more like a bat than a dog" and warned them to look out for them. After Sam finally arrested and sent Corynthia, and Tiger in prison, Fritz along with Flopsy was adopted by him.
Fritz was voiced by Gregory Snegoff, who also voiced Evarard Maltravers, the villain from the other animated Titanic movie, The Legend of the Titanic. Fritz too shares his voice actor with his former major adversary, Geoffrey the cat