"Be Careful What You Fish For" is the fourteenth episode of the tenth season of the animated comedy series Family Guy. The episode originally aired on Fox in the United States on February 19, 2012. When Peter and the guys try to salvage a sunken Mercedes-Benz, Peter half-heartedly promises a favor to a helpful dolphin. Soon, the dolphin moves to Quahog but outstays his welcome at Peter's. Peter tries to reunite the dolphin with his ex-wife in hopes that he will return to the ocean.

This episode was written by Steve Callaghan and directed by Julius Wu. It guest stars Ricky Gervais, as the voice of Billy Finn the dolphin, and Lucy Davis as the voice of Joanne Finn, the dolphin's ex-wife. Both Gervais and Davis starred together in the original British version of The Office.

When Peter and the guys try to salvage a sunken Mercedes-Benz after hearing a news report of a cargo of them sinking, Peter half-heartedly promises a favor to a dolphin named Billy Finn that helps him recover a hood ornament. Billy decides to take Peter up on his offer and see what things are like on dry land. Peter is amused at Billy's sense of humor at first, but Billy soon begins to wear out his welcome and is shown being annoying. When Peter finally agrees to ask Billy about moving on, Billy proposes getting Peter a second hood ornament to keep up their friendship. This stops Peter in his tracks. When Peter discovers part of his problem is his estrangement from his ex-wife Joanne and how it contributes to his loneliness, Peter decides to reunite the couple. After attempts with Quagmire dressing up as Aquaman and Joe dressing up as Neptune did not work, Peter and Billy make a heartfelt speech together and the two dolphins are happily reunited. Seamus later fishes Joe out of the water.

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