give Nature's Variety at try, they seem to like it i think because of the freeze dried coating. The other one I found that Alice and my "kibble picky" Akita like is Orijen.
Alice does the same darn thing to me though too, she'll eat it fine, but then gets bored with it after a few days, so since she has a good stomach (same with the Akita) I keep the Nature's Variety and Orijen on hand and switch it every 3 days or so. If I give either one of them the same food for more than a week, they will only pick at it, then I have to make sure my scavenger beagle lol doesn't get it, so I do what I have to to get them to eat normaly. I also get a differnt flavor in the NV every time I get a new bag so that changes it up and keeps them eating better too. If he liked the Blue, keep that but find another one he likes also and rotate them
You can try canned food mixed in also, Alice really likes Evenger's (I have to change the flavor with that each new can for her too though
)