Related Clues:

• Cod's neighbor in the showcase
• Sock part
• ''O --- Mio''
• Cod's showcase neighbor, perhaps
• Seafood choice
• Pump part
• One and only
• Callous cad
• Sole support
• Height enhancer
• Shoe part that's wiped on 23-Down
• It's under a foot
• A fish out of school?
• Lone
• Achilles' weak spot