Combine limeade, olive oil, soy sauce, garlic and rosemary in a flat dish or gallon size zip-top plastic bag.

Rinse the fresh Steelhead Trout fillets under cold water, pat dry with a paper towel.

Place Steelhead Trout in the marinade, turning several times to coat. Cover, if needed, and refrigerate for one hour.

Preheat grill/coals to medium-high heat. Remove Steelhead Trout from marinade and place on a well oiled grill, 4 to 5 inches from heat.

Cook, turning once, 8 to 10 minutes. Cook until the fillets begin to flake.