Please click one of the two buttons on the selection screen:
Fishing I: Fish do not move.
Fishing II: Fish move after every catch.

You have to remove all fishes from your fish tank because the fish tank is up for cleaning.

Click the board to randomize the setup. A range of small fish will appear which you have to catch.
A the right border the structure of your fishing net (with some holes in it) will appear. The red dot indicates the 'hot spot' (handle) of your net.

Click the board to cast your net.
Then click the board anywhere to haul in the fish you caught.
The board is wrapped, i.e. the left and right borders are connected, as are the top and bottom borders.

In the moving fish version:
After each haul the fish will swim one step, some to the left and some to the right. If two fishes head for the same position, the one swimming to the left has to wait.

Buttons at right border:
Once you have cast your net, you can SHIFT it by using the arrow keys.
Click the ROTATION button at the center of the shift keys to rotate the net by 90 degrees at any time.

You win if have managed to clear the tank in the required number of moves.
The move counter is displayed at he right border.

Variants 1-10: fixed setups.
Variants 11-15: randomized setup, 40 to 80 fishes, the net occupies 20 positions
Variants 16-20: randomized setup, 40 to 80 fishes, the net occupies 12 positions