
In most cases, fussy eaters are dogs that don't consider themselves to be at the bottom of the pack.
One thing to never do is watch your dog when he's eating. I know everybody's said it before, but it's really important. If he's not the leader, he's got to eat quick before it can be taken away from him. Because you worry about him and keep changing his food, you might be re-inforcing a bad behaviour without meaning it. I'm no expert but from my experience, this is often the case.
I find that now I've got 2 dogs, they both eat like their lives depend on it! When my boy was on his own, he would go through periods hen he'd be fussy and wouldn't eat all his food in one go. My approach was just : 'tough'. But having competition has been the best way to solve the problem! Also, i don't change their food all the time, dogs don't need variety and I believe it only causes problems, whether it makes them fussy or disturbs their delicate GI balance.
I would recommend you give your pup a good quality puppy food as it's richer than the adult one, mixed with a bit of tripe to help him put weight on. But don't worry if he doesn't eat, stick to the regime no matter what and don't forget the importance of the feeding ritual in pack animals like dogs. Feed him after yourself (when he's been watching you eat) and don't watch him while he eats. If he's not finished within 10 minutes, take the bowl away without a word or a glance.
Good luck!