Related Clues:

• A small fish - bad one
• Apply light touches of colour to the fish
• Up to no good, and that's flat
• It's no good coming back with this, and that's flat
• The fish may turn stinking, and that's flat!
• It's no good up there, and that's flat
• That fish turns rotten, and that's flat
• Fishy enough to turn rotten, and that's flat
• Fish would turn rotten, and that's flat
• The sort of fish that may turn rotten, and that's flat
• Turn for rot and that's flat
• The fish turns rotten, and that's flat
• Lightly apply
• Blot away, as a tear
• Apply with a cotton ball, say