1. Mix together grapefruit juice, olive oil, 1 dessertspoon marjoram, salt and pepper in a shallow glass dish. Add fish, turn once to coat both sides, then cover.

2. Refrigerate 1 to 2 hours, turning once or twice.
 
3. Preheat barbecue.
 
4. Reserve marinade, and place fish in lightly oiled wire basket. Place fish 4 to 6 inches above hot coals. Grill for 10 to 12 minutes, turning once and brushing twice with reserved marinade, until steaks are barely opaque in thickest part.

5. Arrange on a platter, and garnish with sprigs of marjoram.