Welcome to the board!
There are two Guinea pig foods I am able to find here in BC, one called Living World extruded guinea pig. My Degu's loved it, though I've changed b/c Petcetera is now the only place that carries that food and i don't want to support them so i don't shop there (Plus they charge way to much).... a bummer. Anyways the next good one is called Martins Guinea Pig food, i use their rabbit food too, both great products. I found 1 pet store i could order it from, and now a feed store closer buy. You have to ask if they 'can' carry it, most places will be happy to order you in a bag.
When looking for a guinea pig food make sure it dosn't have cane molases in it (which neither of these brands do). It took me forever to find a brand that didn't have molasses in it. Finding food for a Degu is Canada is tough work but it can be done
This is my Degu mix -
Pretty much just Guinea Pig Pellets, some rolled oats, puffed wheat and a bit of millet mix. But mostly the pellets.
All my goo's are healthy and happy on this diet and it's not super expencive either.
Do you hand feed you Goo treats?
I've just been very lucky, all 5 I have here are super friendly. But giving them hand treats will help win his affection. I know with gerbils, if they are in pairs usually they are more friendly, as the other gives them a bit more confidence so they aren't scared of things as much... but then that's gerbils I'm not sure if it would be the same for Degus.
Good Luck with him, and hopefully he learns quickly how much fun you can be.