Minecraft wiki entry for Sea_Pickle, associated text: Bone meal can be used on sea pickles if they are underwater, and planted on living coral blocks. This increases their number on that block, and they spread to empty areas underwater above other living coral blocks. They can spread to the original sea pickle's level or one level below, out to a horizontal taxicab distance of 2. Bone meal can be used on sea pickles planted on other blocks, or outside of water, but nothing happens and the bone meal is still consumed.[1]