The Chinese haunted house.

A ten year old mystery explained. Two brothers purchased a large house for a pittance, $6,500, because a series of previous owners believed it was haunted. After an investigation lasting several evenings, the brothers discovered the cause of the mysterious noises that had frightened away the previous owners. Located in a sewer pipe underneath the bottom floor, a family of catfish were in residence. Apparently, the first owner of the house had enjoyed catfish dinners and two escaped, providing the genesis of a dynasty.

http://www.weirdasianews.com/2007/12/22/10-year-chinese-haunting-finally-debunked/