Silverfish

Silverfish are small, insectioid hostile mobs found hiding in stone-like blocks in mountains, strongholds, igloo basements and woodland mansions.

Spawning
Silverfish spawn from broken infested blocks, which generate in strongholds, underground in mountains biomes, igloo basements, and woodland mansion false portal rooms. Silverfish do not appear if the block is broken with the Silk Touch enchantment.

Silverfish spawners naturally generate in end portal rooms in strongholds. They can spawn only in light level 11 or lower from spawners and cannot spawn within a 5 block distance of any player. This is the only renewable source of silverfish and infested blocks.

Behavior
Silverfish attack players, iron golems, snow golems and call other silverfish in the area upon being hit. These silverfish can see through walls and pathfind until they reach the player. When they suffer poison damage or damage inflicted by the player and survive, they cause other silverfish within a 21×11×21 area to break out of their infested blocks. The player can prevent other silverfish from appearing by killing them in one shot. Silverfish, being arthropods, take more damage from the Bane of Arthropods enchantment.

When idle, silverfish enter a nearby stone, cobblestone, stone bricks, mossy stone bricks, cracked stone bricks or chiseled stone bricks block, transforming it into the respective infested block if  is set to. They cannot infest mossy cobblestone, despite being capable of infesting both mossy blocks and cobblestone, and they also cannot infest slab and stairs of these blocks. They are also unable to infest andesite, diorite, granite or smooth stone.

Silverfish, along with Endermites, are not all too dangerous, but are considered a nuisance at best because they can be difficult to hit, due to their small hitbox, quick movement speed, and oftentimes unpredicatble movement patterns. While a lone Silverfish poses almost no threat (even a totally unarmoured player is safe from one, as they do minimal attack damage, and can be outran or punched to death easily), a large swarm of 6+ Silverfish can quickly become a serious threat, even to armoured players, as they are prone to pushing players off cliffs, or into other threats, like lava pools. They are particularly annoying in the End Portal room, where they can easily knock an unpreprared player into an End Portal, either sending them into the End when they are not ready, or into the lava pool under the frame. Combined with the fact Silverfish hide inside blocks often, they act as "annoyance" mobs more than actual threats, but they still should be taken care of quickly before one Silverfish turns into a massive swarm.

Drops
Silverfish have no drops other than when killed by a player or tamed wolf.

ID




Entity data
Silverfish have entity data associated with them that contains various properties.

Trivia

 * In real life, silverfish are small, relatively harmless, wingless insects that are often found in dark areas in buildings and the wooden pilings of seaside piers and trees. They are infamous for damaging paper-based products.
 * Silverfish appeared in the April Fools 2.0 update as the redstone bug.