mobs for mobkit:
adds sharks, riverfish, piranha, whales and sea urchins for now.
Also you can add muddy_riverwater by chosing so in the mod settings. The above should be done before starting a map or you have to regenerate parts of the map with /deleteblocks command.
this mod includes an api/library of useful functions and helpers you can use in your own mods. The mobs can be disabled in the settings if you need the api only.
there are also craftable shark buoys to keep sharks away.
This mod needs mobkit, it does not work with mobs_redo.