Possible Clues:

• Causing endless annoyance
• Grating, irritating
• Bad fish is enough to have one feeling bad
• Foul-smelling fish causing irritation
• It's still irritating that the fish should be stinking
• Over-luxuriant heather is causing annoyance
• Foul-smelling fish causing some bitterness
• Continuing to irritate Heather after row
• It will make one sour if the fish is so bad
• The bad fish leaving a nasty taste in one's mouth