When you get an ant infestation here in California, you need to make sure your kitchen is clean with nothing to attact them. But if you have pet food out, they will find it.

In theory, ants won't crawl over some materials like vaseline. But if you coat the bowl rim with vaseline, it will get in the pet's hair.

So I suggest a wide pet bowl with a deep and large groove near the base which you can squirt something like vaseline into. It must be wide enough that ants can't do the living bridge trick to cross it, and deep enough that pet hair won't get into the vaseline. That stuff should stay around for quite some time before needing a refill, though if you dishwash the bowl, you will lose it.