Klaus Heisler
Klaus Heisler is a fictional character from the American animated television series American Dad!. He is voiced by Dee Bradley Baker and first appeared on television, along with the rest of his family, when American Dad! initially premiered on Fox on February 6, 2005, with the series' pilot episode. Klaus is a man whose brain has been placed inside of a fish's body. Once an East German Olympic ski-jumper, he is now the Smith family's hapless and frequently mistreated goldfish.
Personality
Klaus Heisler debuted in American Dad!'s first episode, Pilot, where it is soon revealed that Klaus was once an East German Olympic ski-jumper, until his mind was transferred into the body of a goldfish during the 1986 Winter Olympics by the CIA to prevent him from winning the gold medal, leaving him trapped in the goldfish's body. Klaus still has not come to terms with what happened, at times malcontent and gloomy. Not confined to his fishbowl, Klaus is often seen uniquely scooting himself about the Smith residence, reclined in a dish of water. In the early seasons, Klaus had an obsessive crush on Francine Smith and often made sexual advances to her, but stopped after the events of "Finances with Wolves", in which Stan saves Klaus' life despite his attempt to have sex with Francine. For much of the later seasons, the Smith family and particularly Roger have been shown to treat Klaus with disdain, take him for granted, and even mistreat him. In the later Fox seasons, Klaus was shown to be the smartest and most reasonable character in the family, often trying to warn or advise the Smiths of their wrongdoings of selfishness, stupidity, or recklessness. In the TBS seasons, Klaus developed into a stereotype of bro culture, prone to the Smiths' deranged behavior, as well as a love of Pickle Rick and his "boys" from Tampa.Relationship with Roger
Klaus and Roger's relationship is best described as a sibling rivalry. At times they dislike each other and at other times they get along well. Roger is seen to be incredibly spiteful toward Klaus and insists on trying to make him feel despised, saying things like "You can't participate Klaus, I hate you. I say that not out of anger but as a fact" in "Great Space Roaster" and "It's like you want to be kicked out of this family" in "The One That Got Away". Klaus does things to get Roger into trouble for his amusement, like when he tricked him into eating Francine's potato salad in "Deacon Stan, Jesus Man". When a horrified Roger asked why Klaus would do something like that he just laughed and said "I'm German, it's what we do." In "A Piñata Named Desire", after Klaus made a comment about acting, Roger simply knocked Klaus's fish bowl across the room, smashed it against the wall, and walked out of the room as if nothing had happened while the fish lay gasping on the floor.Among everyone else living in the Smith household, Klaus is very much the most aware and sensible of Roger's contemptuous, abusive, and insanely-vindictive nature of selfishness and lack of morality and occasionally tries to warn the rest of the family against listening to or getting involved with him. Such instances, however, are ignored by everyone's naivety and general inability to take most matters seriously or remember that Klaus is a "man in a fish's body" rather than just a mere talking goldfish, as said in "Dr. Klaustus".
Although Roger has claimed to hate Klaus in the past, they do have a bond and are capable of being civil to each other such as when they head to Europe together in "Red October Sky". Further evidence of this can be seen in "Pulling Double Booty", as Roger and Klaus are quite content to watch a movie together and show annoyance when they must pause it as Stan intrudes with the cookie dough. Another example is that Klaus is often shown in the attic with Roger as he tends his fake bar in many disguises while in "Live and Let Fry" Roger dresses up as Klaus, the human, to help him get access to a family member's will. In the end, it turns out to be a trap to lure Klaus out of hiding and Roger gets beaten up because Klaus owed some money to the East German Mafia. However, Klaus stays with him and keeps him company during his recovery, making sure Roger has sufficient pain medication to help him through it. Klaus was also the only member of the Smith family to remember Roger's birthday in "1600 Candles" and the alien seemed genuinely touched that he had bothered to prepare a birthday surprise for him.
Klaus and Roger engage in a sexual relationship in "Kloger", but Klaus breaks it off when Roger starts to want to act like a real couple, as Klaus was only interested in the taboo aspect of sneaking around the family for their relationship.