This works with: salmon, halibut, swordfish, tuna and pardon me, beef or pork.
Lather your fish in olive oil, now put plenty of oregano, garlic powder, course ground black pepper, a little sea or Kosher salt. By the way I do a different sequence with each side of the fish as I start putting garlic powder on first on one side and on the other I might start with the oregano! Let it sit 30 minutes, more if in the fridge. Get the grill real hot. Time on the grill matters as we tend to do tuna about three minutes+ a side, swordfish/four, salmon/five, etc; you'll get the feel. By the way in Coastal magazine I read some recipes where a noted chief said he could cook anything with only five spices. What I like about Cap'n John's rub is, it is made with what we all have already in the galley!!!!!!!!!!!!!!!!!!