Wolf of Wilderness Monoprotein Fish "Vast Oceans" - dog dry food

My Labrador (who has allergies) used to really enjoy this food, it never caused any problems or allergic reactions. However, the last bag I opened three days ago gave him stomach pains and diarrhoea. He refused to eat it, which is very unusual for a Labrador (he was still interested in other treats, just not the food). If this is due to a change in the ingredients, it definitely should have been clearly marked!! The food has been discontinued and my dog won’t be going back to it.