Quinoa. There's some good suggestion on the search on this site.

New red potatoes with a peeled stripe all the way around cooked in butter and finished with flat leaf parsly (salt and pepper of course) and I like to add a little white wine to them. Although, serving with asparagus the wine might not be a good idea. Not sure pairing asparagus as a side with fish is a good idea though. I try to serve sides with fish that don't compete with it. And when serving or eating fish I like to pair wine with it and that would be bad with asparagus. Just my .02 cents.

Tad's roasted potatoes:
http://www.food52.com/recipes/2532_tads_roasted_potatoes
Fabulous!

Plain, steamed white rice or a rice pilaf would work.