Dog Food Salmon Sweet Potato

best low-allergen dog food?

like fish and sweet potato, or any other unusual ingredients. (but still of high quality)
no lamb/chicken/salmon.
i’m trying to see if my dog’s allergic to one of those.
i’m not considering anything that has by-products, preservatives, fillers, sugar…etc.
so don’t answer with a dog food that includes one of those, please.
also, i’m thinking he might have hot spots instead of allergies. we’re going to the vets soon to make sure, but i’ve also heard hot spots are a result of an allergic reaction to what he’s eating. is that true? and will changing the dog food help?

http://www.omhpet.com/wellness/dog_wellness_simple_food_solutions_index.html
I’ve been happy with this food,
Hot spots can often be caused by allergies,changing food is a good idea.

Abigail plays with Ci Ci