Resting meat so that it will reabsorb its juices is a myth and results in cold meat. There is a big difference between resting meat, that is letting it cool, and holding meat in a warming oven, which should be avoided. There are many reasons why you should not rest meat: 1. it continues to cook, 2. it can get rubbery, 3. it does nothing for the juices unless you get it cold enough that it will congeal, hardly what you want to do when serving meat, 4. usually the meat will spend considerable amount of time on a plate in front of a diner before it is eaten.
I never rest my flank steak or any of my other steaks when serving them at the Hudson River Valley Art Workshops. And those steaks always come out juicy and delicious.
Keeping this in mind, I never, ever rest my fish. Why? Because I want it out to the diner while it is still hot, while it is at its peak. (Pet peeve is when diners wait to eat the food put in front of them until everyone of them is served. Usually at my restaurant, we have tables of no less than 8 to 12 people and this will mean cool food.) If you want juicy fish, or meat, for that matter, cook it right. My fish is always juicy and tender and perfectly cooked, not overcooked from resting. I am careful how I cook any meat but doubly so when cooking fish. I always take it out when it is 5 to 10 degrees cooler than my target temperature. And with delicate fish, I often use a coating or a cooking technique such as en papillote or en croute to protect the fish, which are also coatings of sorts.
And don't forget, the slower you cook a piece of meat, the less bunched the protein will be. Cooking meat at high temperatures, makes the protein bunch into a hard "knot". Slow cooking allows the protein to stay stretched out and tender. Also, with roast, cut against the grain. With fish, do not overly handle the fish. Avoid turning if you can. I hope this helps. See: http://amazingribs.com/tips_and_technique/mythbusting_resting_meat.html for reference and also see this article as a counter example: http://www.seriouseats.com/2009/12/how-to-have-juicy-meats-steaks-the-food-lab-the-importance-of-resting-grilling.html