A Mob to find in a sea church

The idea is to get a barracuda inspired mob that lives in packs and moves really fast (essentially evil dolphins). It would drop small fish that it had eaten and be aggressive toward drowned and the aforementioned fish. The fish killed by barracudas would not drop anything, as the barracuda eats them. On the off chance they meet a guardian, they would be neutral toward them and have a sort of rivalry. 

The corresponding structure; https://feedback.minecraft.net/hc/en-us/community/posts/360067883652-A-new-underwater-structure