Java Edition 18w15a

18w15a is the thirty-first snapshot released for 1.13.

Additions

 * Blocks
 * Blue Ice
 * Generates in icebergs.
 * More slippery than ice and packed ice.
 * Crafted using 9 packed ice.
 * Conduit
 * Crafting recipe: 1 Heart of the sea + 8 Nautilus shell
 * Can be activated by placing prismarine, prismarine bricks or sea lanterns around it.
 * When active, will affect nearby players in water with the Conduit Power status effect.
 * Conduit power stops the breath meter from running out, gives underwater night vision and increases mining speed.
 * A complete structure will fully power the conduit.
 * When active at full power, the range will increase and hostile mobs within 8 blocks will take damage.
 * Emits a strong glow, at light level 15.
 * Displays as if its  tag were set to true, though it has no such tag.
 * Possibly means that this block can't be placed outside of water (like how seeds can't be planted on grass). (unconfirmed)


 * Items
 * Heart of the Sea
 * Used to craft conduits.
 * Not available currently in survival.
 * Nautilus Shell
 * Used to craft conduits.
 * Can be obtained by fishing.
 * Drowned occasionally spawn holding a nautilus shell.


 * Entities
 * Dolphins
 * Spawn in any ocean that isn't frozen.
 * Neutral mobs. Like wolves and zombie pigmen, dolphins will attack in groups if one is angered.
 * Can be fed using raw cod, but they don't breed.
 * Drop cod on death.
 * Play with nearby items by picking them up and dropping them after a very short moment.
 * Occasionally jumps out of water like real-life dolphins.
 * Can also jump between disconnected bodies of water.
 * Chase after boats and jump over water surfaces.
 * They suffocate after spending too much time on land, despite having lungs


 * Options
 * Added Biome Blend distance video option


 * Structures
 * Icebergs
 * Generate on frozen oceans.

Changes

 * Blocks
 * Ice
 * Mobs can now spawn on top of ice.
 * Water
 * Has a new texture.
 * Now only blocks 1 light per block, instead of 3.
 * This only affects newly placed water.
 * Underwater vision from previous snapshots is gone: water is darker at lower depth.
 * Ocean variants have their own water colors, and the swamp water color was changed.
 * In newly generated chunks, you're less likely to find frozen ocean next to warm ocean (and similar).


 * Swimming
 * You can now swim through one block holes.
 * The transition between swimming and normal state is now smoother.
 * Sprinting at the surface of water no longer makes you swim, instead you stay at the same altitude constantly.


 * Other
 * Optimized fog rendering