You can now fish up shulker shells in the end instead of nautilus shells.

This was removed as Mojang made shulker shells farmable and the feature required a large manmade pool to use.

History

1.0.0X

This was a tiny tad unbalanced, and never really worked properly because of the open water requirement to get treasure. You would have to make a massive water pool for this feature to go into effect, which isn’t something that most people would do.

Additionally, Mojang added their own method for renewable shulker shells, making this pretty much worthless.