Jim Miller has made fish at almost every rally he worked. Numerous folks have asked for it. Sadly, my memory is really long. I found this in a 2005 newsletter. Below is his secret.
Fish Marinade
1 tsp salt
3 cloves minced garlic
3 Tbsp olive oil
2 Tbsp lemon juice
3 tsp cajun seasoning
1 tsp black pepper
Mix all ingredients and allow to stand. Then pour over fish. Allow fish to marinate 2-4 hours, then grill.
I use less cajun seasoning and pepper. I make several batches at once and store in the refrigerator.