Marlin is looking at us with a worried expression, lost in the vastness of the ocean with no escape in sight. To his left, a giant blue whale looms overhead seemingly ready to swallow up anything in its path. Nemo bravely ventures closer to the whale, showing no fear. To emphasize Marlin's worry, I suggest coloring him in different shades of blue and gray. Use bright colors like yellow and orange to bring out Nemo's spirit and courage. As for the whale, use a light blue to capture its peaceful aura. The two characters should be strongly contrasting each other, with brightness surrounding Nemo while worry engulfs Marlin.