Hi,
About a month ago my family got a new chocolate lab. Before this dog we had a zoo yorkie mix. At first they both got along fine but now the yorkie (rusty) won't eat around the lab (tucker). About a week ago we had to change both dog's foods because our vet told us not to feed rusty puppy food which we were doing when we first got tucker. But when we switched their foods both animals got diarrea. We now have them on a stable food for about 2 weeks now and they both will eat it. But now rusty refuses to eat when rusty is around. Even when we separate them he will turn his nose up at the food. He only wants to eat tucker's food which is wet puppy caesar food rather than his adult caesar food.
Help!

Sound like he's on a hunger strike. He wants wet food, puppy food too. When he gets hungry enough, he'll eat his own food. Don't break down and give him the food he wants. Make sure he gets plenty of attention too.