In a fit of insanity (plus being bored of eating beef and chicken and pork), I bought myself a bag of frozen mahi-mahi fillets the other day. For a lack of ideas, I thawed a couple filets and pan-fried them in olive oil. (Note that I do not trust this stuff to be sashimi quality.) I threw in some onions and mushrooms too, mostly as an afterthought. While it wasn’t a bad meal, it wasn’t exactly a taste sensation.
I know that it’s possible to denature fish proteins with an acidic enough solution, but I’m a little wary of that style of cooking because you’re not using any heat to help kill the bacteria as well as denature the proteins. However, I was thinking of maybe getting a nice citrus marinade and at least marinating the fish, if not denaturing the proteins with it.
Any Dopers out there experienced with fish? And can we please avoid the inevitable “fish taco” jokes?
Ahh, yes. Mahi-Mahi, the fish so nice that they named it twice. 
I am not experienced with the denature process. Actually had to ask me other half what it was. He said it is when the acid “cooks” the fish. It doesn’t cook it. But he said if done correctly it is good. He only recommended that it be fresh fish and not frozen. Fresh is the key.
You could put the cajun spices to it and blacken the fish. Then use alfredo sauce over the top of it. Serve with your favorite low carb veggie. Very tasty on another one of my favorite fishes Tilapia. Very nice white mild fish.
Another idea is lay out a piece of wax paper. Place your fish in the center of paper. Decide what you are going to use to marinate the fish. Pour the marinade over the top of fish. You could use citrus or lemon pepper. Put broccoli or whatever veggies you wish in with it. Top with slices of lemon. Get creative. Take another piece of wax paper and place it over the top of your concoction. Crimp the edges all the way around. Throw in the oven and cook. The wax paper seals in the flavor as it is cooking.