As a whole, Atlantic mahi mahi is rated as an excellent, sustainable seafood. They mature quickly and can repopulate fast enough to keep up with reasonable demand for it. If using frozen mahi mahi, thaw according to your package directions. This fish has mild flavor and relatively firm flesh, so it just requires a brush with a little olive oil and a sprinkle of seasoning to make it taste great. Avoid over-handling the fish once you place it on the grill to keep the fillet intact and ensure beautiful sear marks.