PaperMC/nms-patches/BlockCoralFan.patch

--- a/net/minecraft/server/BlockCoralFan.java
+++ b/net/minecraft/server/BlockCoralFan.java
@@ -17,6 +17,11 @@
 
     public void a(IBlockData iblockdata, World world, BlockPosition blockposition, Random random) {
         if (!b_(iblockdata, world, blockposition)) {
+            // CraftBukkit start
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.callBlockFadeEvent(world, blockposition, this.a.getBlockData().set(BlockCoralFan.b, Boolean.valueOf(false))).isCancelled()) {
+                return;
+            }
+            // CraftBukkit end
             world.setTypeAndData(blockposition, (IBlockData) this.a.getBlockData().set(BlockCoralFan.b, Boolean.valueOf(false)), 2);
         }