Now that cave & cliff update is announced as minecraft's newest update, there are so many ideas of what I hsve, but here's one of them: The Bonny Fish. This fishes are around the cave lakes, they have the ability to pretend that they are death, not moving at all. But, when the player swims at a side of them, there's a chance that some of this fishes will come to life and with their glowing eyes they will chase you until you come out of the lake and they pretend that they are death, waiting for their next victim. This fishes have the appearance of a pirahna, but made out of bones and they are bigger than any fish in the game, but not exagerated. You can found them almost all over the cave lakes, in the top of the lake or in the deep of the cave lakes. They can be carried out with buckets, but be sure that you cover all the aquarium, or they will die (more than they are). They will drop 1 to 2 bones.
You can only carry in a bucket the bonny fishes that are alive.
They deal 1 heart and a half hearts in easy, 2 hearts in medium and 3 hearts in hard.
As they are consider undeath they smite enchantement is efficient to deal with them. This fish hsve 5 hearts of health.
As they are considered enemies, they desappear in peacful mode.