I have two Persian cats both of them are less than two years old. I have always given them dry and wet food, however they have been vomiting a lot over recent months so I took away the wet food and now they just have a limited supply of dry food and a water fountain. They haven't seem to miss the wet food but I guess I wouldn't really know? Is it okay to just leave them on a dry diet, and if so is there a good brand that I can buy to make sure they're getting everything they need? Or is it imperative that I re-introduce the wet food? They are indoor cats if this makes a difference.