What are some good side dishes for this recipe? Also, is there a sauce anyone recommends with it?

Interesting. This is an old thread, and people have found many sauces and sides they like to serve with it.
But/and Kristen Miglore's version simplifies Eric Ripert's original recipe a good deal.
She basically seasons with salt and pepper, while he includes herbs (thyme & chives), vegetables (mushrooms &/or asparagus), and port-sherry reduction as a sauce.
So we could all go back to Ripert for ideas of sides and sauce.
http://www.aveceric.com/all-recipes/crispy-chinese-spiced-black-bass-with-porcini-mushrooms-and-port-wine-reduction
https://www.bonappetit.com/recipe/eric-riperts-red-snapper-morels-port-reduction

We just had it with smooth, buttery whipped potatoes. Made a sauce of 1/3c yogurt, 2 TBS dill, 1 small garlic minced, and s+p. DELICIOUS meal.

Thanks everyone!! went with a lemon herb sauce, roasted asparagus, and a pea risotto - turned out delicious!!

An aioli with finely chopped preserved lemons and parsley would be a good all around fish go-to sauce.All of the above side dishes sound yummy.

I like Chimichurri sauce on fish.

Romesco sauce goes well with simply prepared fish (e.g., roast or sauteed.) There are many variations, but this is Jose Andres': http://www.spanishsuitcase.com/features/recipes/receta-jose-andres-romesco/

Steamed or grilled asparagus would go well with the fish & sauce; roast or steamed new potatoes would also be a good pairing.

Céleri rémoulade would be lovely. As would a nice watercress salad--something citrusy and bright. The pea purée mentioned above sounds good, but you could also use favas or soybeans to great effect.

I vote for the asparagus as well, but wrapped with prosciutto or turkey bacon and with a nice balsamic-butter sauce. Sounds like a great meal to me!

I agree with PMarie on bernaise (a tarragon flavored sauce). And asparagus are in season right now.

a simple fennel salad, quinoa, sauteed spinach with garlic

On a hot day I would eat it with crispy vegetable slaw salad, perhaps carrot, jicama, red peppers and/or celery, with herbal vinaigrette. In spring, maybe fennel slaw or green pea pure. Lemon risotto.

bearnaise and asparagus and snowpeas

Right now, I'd go for an Italian salsa verde to be served on the side. And in that case, I'd serve with orzo or couscous and sauteed greens.

I think there are other serving ideas in the comment thread on the recipe too!