Tutorials/Axolotl farming

Axolotl farming is a way to collect axolotls as well as glow ink sacs from glow squid. Two basic methods of farming axolotl are available: breeding and natural generation.
 * Breeding axolotls is the only way to gain the rare blue variety of axolotl.
 * A natural generation farm causes axolotls to spawn, and the spawn conditions are also correct for glow squid.

Breeding
Breeding adult axolotls requires buckets of tropical fish. This a time-consuming manual effort. Feed two axolotls to put them into love mode, after which a baby axolotl spawns. The parents have a "cooldown" period of 5 minutes $$ or 1 minute $$ before they can be bred again. The baby axolotl has a $1/1200$ chance to be blue, otherwise it inherits the color of one parent. A baby becomes an adult in 20 minutes (or sooner if you feed it), after which it can breed.

Once you have a blue axolotl, you can breed it to gain more blue ones, because each new baby has a 50% chance of inheriting the color of one parent.

Considerations
The problems with breeding are time and resources. Because you need to breed axolotls many times before getting a blue one, you need many tropical fish. Consequently you need many buckets, which in turn require many iron ingots to craft. Some advanced items to make things easier are:
 * A chest full of shulker boxes helps keep your inventory of buckets manageable.
 * A conduit allows you to breathe and see better underwater for the purpose of hunting tropical fish and breeding axolotls.
 * Without a conduit, a helmet enchanted with Respiration is a must. You can obtain these via zombie farming in Hard difficulty, or you can use an anvil to combine a helmet with an enchanted book obtained via fishing or trading.

Location and breeding pen
Once you have the materials you need, find a warm ocean and create a large holding pen for your axolotls. You can do this on land next to the warm ocean, or simply cordon off a section of the ocean, or carve an inlet into a beach. Build the pen so that the walls are at least one block higher than the water level, to prevent the axolotls from escaping. You can put a ladder in the pen to allow you to get in and out.

The breeding pen doesn't have to be deep. One layer of water is sufficient for axolotls to breed. A shallow breeding pen allows you to feed the axolotls without having to swim.

In Java Edition, drowned don't spawn in shallow water, although they can in Bedrock Edition. Either way, light up the border around the pen to prevent hostile mobs from spawning in it.

Breeding stock
You need to find two axolotls to start breeding. Swim around, go into underwater caves and canyons. When you see an axolotl, use a water bucket on it to capture it. The bucket must not be empty when you do this; it must contain water.

Food supply and breeding
Hunt for tropical fish, using as many water buckets as you can carry. When you feed your axolotls to breed them, it is a good idea to hold one bucket of tropical fish in your off-hand to maintain the axolotls' attention. If not, as soon as you feed one, you are holding an empty bucket, causing the axolotls to lose interest and swim away until you switch to another bucket of fish.

With luck, you might get a blue axolotl before you have bred 1,200 non-blue ones.

Natural generation farm
For axolotls to spawn, they require a water space below sea level in total darkness, with natural stone block (stone, deepslate, andesite, diorite, granite or tuff) within five blocks below the spawning space. These conditions can be achieved in an underground room filled with four or five layers of water. Additionally, Bedrock Edition requires the ceiling of the room to consist of opaque blocks.

Hollowing out the spawning room yields sufficient andesite, diorite, or granite that you can use to replace any undesirable blocks in the floor. The floor should not include any cobblestone, sand, gravel, ores, or dirt.

The conditions that cause axolotls to spawn also cause glow squid to spawn. Because axolotls kill squid, you can arrange the farm so that the glow ink sacs dropped by the squid are swept into a collection chest. Or if you don't care about glow ink sacs, you can make the farm even simpler by ignoring them; the ink sacs disappear after 5 minutes.

The example farm described below is easy and quick to build in survival mode with common materials and stone tools. In fact, if you are interested in breeding a blue axolotl, it may be easier (and safer!) to build a simple farm to get your breeding stock, rather than hunting for axolotl in the wild.

Location
It is best to build your axolotl farm well away from an ocean or Lush Caves biome (although you might be able to adapt a Lush Caves location into an axolotl farm).

If you build this farm near an ocean, you risk axolotls appearing in spawnable locations outside the farm, and the farm may have a poor yield, with an axolotl or glow squid spawning in it only rarely. This is particularly true if there are underwater caves or ocean monuments within the mob despawn radius, because these features create conditions that allow axolotls to spawn.

Pick a location on land outside the mob despawn radius (128 blocks in Java Edition, 54–128 blocks in Bedrock Edition depending on simulation distance).

The ceiling of your farm must be below layer 63 (sea level). Any depth should work, although the floor of the farm should not be below layer 0 in Bedrock Edition. The distance between the floor and ceiling should be at least 5 blocks.

Example farm
The diagram below illustrates the concept. The spawning room area is 8×8, and 5 blocks high. The 8×8 dimensions were chosen because it requires only one hopper, but different room sizes and shapes are possible with a carefully planned arrangement of flowing water and hoppers.

Water source blocks occupy the bottom four layers of the room. The fifth layer has a row of water source blocks on one side, and one more opposite the hopper, to create a water flow that pushes items toward the hopper.

The hopper should be two blocks below the flowing water (one block below the top-most water source block). Placing the hopper just below the flowing water layer (which would be normal for water flowing on top of a solid surface instead of on top of more water) risks items getting trapped under the hopper. Place buttons or signs on one wall above the hopper to prevent water from flowing in. Then, when an item is pushed into the corner by the flowing water, it falls one block down into the hopper.

If you don't care about collecting ink sacs, you don't need the hopper or flowing water, and the farm becomes trivially quick to build. Just make the room six blocks high and fill it with five layers of water, leaving the top layer as air for you to breathe and put temporary torches for lighting.

Water flow management and item collection
The flow in the top layer is managed by first placing the row of water blocks along the wall, which makes a short waterfall into the next row but does not extend all the way across the room, as water would normally do on a solid surface. You must place a row of easy-to-break blocks just underneath the waterfall row to force the water flow to extend one more row. For this purpose, slime blocks, honey blocks, and TNT can be mined instantly without tools, and dirt can be broken quickly with a shovel. Break the temporary underwater blocks and repeat for the next waterfall row, working your way all the way to the opposite wall to get the top layer of water flowing from one wall to the other. Finally, place a water block opposite the hopper to cause the combined flows to sweep all floating items into the hopper.

An upside-down cobblestone stairs block is placed above the chest to prevent axolotls from leaving the room but still allow the chest to open. A block of sand is placed in front of the chest to provide a final seal to prevent any light from reaching the interior of the room. You just need to break this block to open the chest.

Back door access
There is ladder in the entrance area near the chest to get in and out of the farm. A path runs from the entrance around the back of the spawning room, leading to a door at the corner opposite the hopper. Due to the circuitous path and distance from the torch in the entrance area, no light reaches this door. This door is useful for entering the room to catch axolotls that spawn.

The path that runs around the back of the room is dark by design. This means that hostile mobs can spawn there. It is a good idea to line the path with bottom slabs to prevent any mobs from spawning in that path.

You should be able to see the door sufficiently in the dark to open it, or you can place a temporary torch in the hallway. Just be sure to remove this torch when you leave.

Operation
Once you have removed your temporary torches and blocked all the light from your chest collection room, the farm is active, but you need to move yourself more than 24 blocks away from the farm for anything to start spawning in it.

Glow squid spawn more easily than axolotl, but when axolotl spawn, they start killing the glow squid, causing them to drop their ink sacs, which float upward and are swept into the collection chest, which you access by removing the temporary block of sand that's in front of the chest to prevent light from entering the room.

To gather axolotls, go through the back door with buckets of water. Even though the hallway is pitch dark, once you pass through the door into the water, your underwater vision is sufficient to see axolotl in the room and catch them in your water buckets. An axolotl may wander out the door into the hallway. That's OK, you can still catch it. If you want to keep axolotl around, you need to interact with them (feed them, breed them), otherwise they may despawn again.