Gus and the Greatest Catch of All by Victoria Cossack
Gus was the best fisherman in all of town...no contest (although he'd won many). Gus is trying to break his own record of most fish ever caught. When he falls overboard, he must change his tactics. He follows a clever, shape-shifting school of fish and comes to realise that it's more fun when fish are friends, not food. Accompanied by whimsical art, this aquatic story hints at the importance of conserving sea life and shows that, if you get to know someone, they just might change your perspective and end up your friend.