Related Clues:

• A sandwich filler
• Ear-shaped shell
• Salad addition, sometimes
• Skipjack
• Casserole option
• Salad ingredient, sometimes
• Mollusk with an iridescent shell
• Fish in a melt
• Bluefin, e.g.
• Type of fish
• Salad fish
• With 78-Across, fishy deli sandwich
• __ melt
• Gastropod with a pearly shell
• Canned fish