Pufferfish are uncommon defensive mobs found in oceans.
Fish spawn underwater at around 12–32 blocks away from the player.
Pufferfish spawn in lukewarm, warm, and deep lukewarm oceans in groups of 3–5. In Bedrock Edition, they spawn only in warm ocean biomes.
The player may collect a fish by using a water bucket on it, which gives the player a bucket of fish. Fish placed with buckets will not despawn naturally. When that fish bucket is used against a block, it empties the bucket, placing water with that fish swimming in it. An empty bucket may be used as well. (Legacy Console and Bedrock editions only)
Unlike other fish, pufferfish don't swim in schools.
Like other fish, pufferfish cannot survive out of water. Outside of water, they flop around like guardians for a while until eventually they start to suffocate and die like squid. In Bedrock Edition and Legacy Console Edition, they will rotate when flopping. Fish cannot swim or breathe in cauldron water.
Pufferfish will puff up when approached by a player in Survival or Adventure mode, drowned, or any non-water mob inside of a 5x5x5 block cube around the fish, going from unpuffed, then semi-puffed, to fully puffed (Java Edition only), or instantly to the fully-puffed state (Legacy Console and Bedrock editions only). Pufferfish are technically considered as passive mobs but going near one when fully puffed will inflict the player/mob with seven seconds of Poison, and touching them in their puffed or semi-puffed form will deal damage separate from the poison. Pufferfish also instantly puff up to their fullest form after taking any kind of damage. (Bedrock Edition only) After puffing up, they will slowly deflate to their normal shape. Undead mobs are unaffected by the poison effect, but still take damage when they come into contact with pufferfish.
- The pufferfish in Bedrock Edition has no animation for the second or third stage of the pufferfish.