What's a good vegetable and/or grain side dish to serve with fish tangine?

I ended up making kale, mushroom and feta cheese hand pies along with Israeli coucous.

Since you already have a starch w/ the couscous, i would suggest greens and/or beans. kale or swiss chard sauteed w/ minced garlic and served with lemon. and kidney beans (for color and creaminess) cooked with onion,and moroccan spices and stock.

Mirepoix comprises a sautéed mixture of diced vegetables such as carrots, celery, and onions.

I would use couscous with a very finely chopped mirox poie. You can also buy "Israeli" couscous which is a larger bead and can be served by itself (spiced of course) and your favorite veg on the side. But, have you considered putting the veg into the tagine with the fish and broth?