Well, looking up "hoof" on Wikipedia, I found that it is

the tip of a toe of an ungulate mammal

And apparently an extinct ungulate, Mesonychid, was carnivorous and also had

four digits that ended in tiny hooves on all of their toes and were increasingly well adapted to running.

Regarding their diet:

Many species are suspected of being fish-eaters, and the largest species are considered to have been scavengers.

They are also considered to be related to cetaceans, some of which are carnivores.

So it seems like hoofed creatures can adapt fairly well to eating fish.

I've also heard that other ungulate species, like pigs, can be fairly omnivorous even if not truly carnivorous.

Well, looking up "hoof" on Wikipedia, I found that it is

the tip of a toe of an ungulate mammal

And apparently an extinct ungulate, Mesonychid, was carnivorous and also had

four digits that ended in tiny hooves on all of their toes and were increasingly well adapted to running.

Regarding their diet:

Many species are suspected of being fish-eaters, and the largest species are considered to have been scavengers.

They are also considered to be related to cetaceans, some of which are carnivores.

So it seems like hoofed creatures can adapt fairly well to eating fish. However, the shape of the teeth is more important.

I've also heard that other ungulate species, like pigs, can be fairly omnivorous even if not truly carnivorous.