Fail, go bankrupt, as in This company's about to go belly-up. This expression alludes to the posture of a dead fish in the water. [Slang; early 1900s] Also see go broke.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.