Talk:Quests/@comment-27058561-20151009140510/@comment-26891284-20151009222040

It does indeed seem that the quest is to get three mackerels. However, you don't have to do so in world 3 -- I got it from getting three mackerels from 1-5.

Once you finish it, another one takes its place, which I'm guessing is to get 10 mackerels?