Combine vinegar, soy sauce, gingerroot, sugar, garlic, chili; pour over fish steaks; cover and refrigerate for 30 minutes.
Spray grill rack with cooking spray. Heat grill to 380°F Save the marinade; Place fish on grill and cook, skin side down, for 7 minutes, turning once and grilling 3 more minutes, or until fish flakes with fork.
Place marinade in saucepan and bring to boil.
When fish is ready, use marinade for dipping sauce.