Fishy Sudoku

Devil Ray puzzles may require X-Wing, Y-Wing & Swordfish techniques. Not for beginners!

To enter a number, click the square and type the number.

To edit pencilmarks, hover the mouse over the top third of a square and type a number to add or subtract it from the pencilmarks.

Red pencilmarks are lone remaining candidates. Click near any red pencilmark to set that square to the red number.