Related Clues:

• Gripe, gripe, gripe
• Bottom-feeding fish
• Make ghost noises
• Sound stressed, maybe
• Verbalize an ache
• Bottom feeder
• 21-Across. e.g.
• __ and groan
• Fault-find
• Koi
• Music to a punster's ears
• Find fault with fish?
• Be a nitpicker
• ___ and groan
• Trivial complaint