My Parents Are Aliens (1999) : 7x14

Josh needs an alibi from Harry to cover himself from some misdemeanor, but Harry of course refuses. Trent advises him he might have more success if he broke a habit of a lifetime and tried being nice to her. He gives it his best shot-but to no avail. Sophie causes Lucy yet more embarrassment-this time at the swimming baths where she makes a fool of herself sinking instead of swimming. Sophie takes herself off to the river to practice and morphs a spectacular tail but fails to morph back owing to the pollution of the water. As a result the family have to cope with a new Sophie in mermaid mode. And she has a spectacular effect-not least on Andy The Freak. Fed up with losing to CJ from Hide-And-Seek, Brian changes the geography of the house and causes chaos for the whole family. This is the only other episode where the bathroom in the Barker/Johnston household is seen.