This was really charming! I liked how many little mysteries there were to uncover. The alternate movement mode really made me laugh.
I finally figured out the fish after I'd found all the light houses, which was a bit too late. Cool idea for a mechanic though. Maybe the fish could have some dialogue before jumping back in the water? I feel like that shows up in a lot of folktales. "Spare my life, and I'll..."
I found the anchor a little hard to aim. I'm not sure what causes the arrow to be larger or smaller, and it seemed like sometimes a very large arrow gave me quite a short throw. I like the concept though, and it was fun to throw the anchor over an island and have the boat sail around it.