Существо: minecraft:pufferfish
Морская траваminecraft:seagrassFeed pufferfish seagrass or kelp to breed them and increase their number in the Aquarium.
Using a sword or axe on the Aquarium will kill the pufferfish and drop its loot.
Ведро водыminecraft:water_bucketYou can pick up pufferfish from aquariums using water bucket.