Starting from the Catcher, each player draws 1 Fish card from the deck for each ID card they have.
At the end of the Round, the Yellow penguin, who was a Catcher, has caught the Red and the Green penguins and so they draw 3 Fish cards.
The Blue penguin has their ID card in front of him still, so they draw 1 Fish card.
The Red and Green penguins don't have any ID cards in front of them, so they receive no additional Fish cards.