When MacDallan slipped in a river while fishing. He seriously fractured and lacerated his skull along with possibly fracturing one of his legs, Fisher kept him from drowning by keeping his head out of the water with his carry-net. Fisher also managed to improvise bandages for Dr. MacDallan's head wounds by cutting the sleeves of his shirt and tying it around his wounds and stopping the blood loss. He helped Dr. MacDallan splint his ankle by holding the spare fishing rods so that MacDallan could tape them to his leg. He possibly saved MacDallan's life a second time when he cushioned the human's head with his own body after MacDallan stumbled and fell, injuring himself in the process.
Fisher and MacDallan bonded during the experience, and lived together from then on. They later uncovered the fact that Dr. Muriel Ubel had caused an enviromental disaster and to cover it, murdered several people by causing their aircar to crash. (HHA2.1: TS)
He and MacDallan remained fishing fanatics, and would go on many fishing trips together. (SK1)