"Blue Sea" : an interesting book. There is a little fish. Then a big fish comes along and then a bigger one and at last the biggest fish shows up and everyone swims fast because they don't want to be eaten up by the biggest fish.
There is a big hole. All fish swim through but the biggest fish gets stuck. Then there is a smaller hole and the bigger fish gets stuck and a smaller one ... until only the little fish can swim through and be safe.
Now, that we know the book, let's play the game. You all have fish. First, let's try the BIG hole.
All fish went through. Let's try a smaller hole.
Hm, some fish got stuck! And a smaller one ... more fish got stuck.
Look! Only the little fish were able to go through the smallest hole... just like in the book. You did it, Leaves 1!