He eats Nutro Natural Choice Fish Meal. It's like $55/30lbs. He was getting pretty chronic ear infections for a while and the vet suggested a food trial before an allergy test ($$$). I was very skeptical, but, man, he has not had an ear infection in about a year since the switch. She said we should try a "novel protein" and suggested some super expensive food that we used for 6 months or so. Royal Canin Duck and Potato. It's like $90 for 25 lb bag. I grumbled about it to start, but it did the trick. We were able to switch over to the much more affordable Nutro, add in Zuke's treats and Greenies, and still we have no ear infections.
Anyway, going to the vet soon. We'll see what they have to say. He's been throwing up all morning.