He stretched out his arms toward the dark water in a curious way
Gatsby is actually reaching his arms toward the green light across the bay. That Gatsby is reaching toward something so far away and, in Nick’s mind, minute, means that this symbol is desired by Gatsby.
This line also ties into one of the final lines of the book: “Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eluded us then, but that’s no matter — tomorrow we will run faster, stretch out our arms farther…. And one fine morning ——”
To help improve the meaning of these lyrics, visit “The Great Gatsby (Chapter I)” by F. Scott Fitzgerald and leave a comment on the lyrics box