I also was never able to catch bastore sardine. Correct location/rod/bait, always received you don't catch anything notification. After 20-30 minutes without catching one, I just switched to moat carps.

Just piggybacking here... can confirm it's the rod causing issues. Composite + sabiki will allow these to be caught as early as level 3. I believe you get skillups on them well into the 20's. Keep them to sell back in windy or for fish broth cooking recipes (~30 cooking).

Can now confirm it was the Clothespole which was the issue as I managed to save enough to buy a Composite and now, back in windy catching Sardines and Quus.