This guide is designed for players eager to learn everything about mobs. Here, I will provide information on the silverfish in Minecraft PE
Silverfish are classified as hostile mobs (they attack players when they come into their line of sight).
Silverfish are the smallest hostile mob (only the end silverfish, which does not exist in MCPE, is smaller). They spawn when certain blocks are broken by the player (which can be disguised as stone, cobblestone, or stone bricks) found within fortresses. Much less frequently, silverfish can also be encountered in mountainous areas.
As mentioned earlier, silverfish are hostile mobs, so they will immediately start attacking a player upon detection. Fortunately, their attack is very minimal: just 1 hp (half a heart). In addition to searching for hidden blocks, a silverfish spawner can be located in a fortress near the End portal. You can create a silverfish farm using wolves to protect the player. This is quite easy since silverfish do not deal significant damage.