If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
In this game you have a number of fish on the playing board. If one fish is located next to another and there's a free space on the other side, the fish can jump over the other fish. The fish that has been jumped over disappears. Your goal is to make all fish, but one disappear. It seems pretty easy in the beginning, but gets much harder afterward.
This game is played with mouse only.