Make salsaPeel and segment grapefruit, orange, lemon and one lime (chop if desired).
Add olive oil, salt and pepper. Toss to combine in small bowl and set aside.
Squeeze remaining lime over red onion in a separate bowl and let it sit in the juice for 10 minutes while you cook the fish.
Make corvinaIn a non-stick pan, heat 2 tsp olive oil over medium high heat.
Sprinkle both pieces of fish with salt, pepper and minced garlic.
Carefully place fish in pan, laying it away from you, not toward you. Cook undisturbed for 4 minutes.
Turn heat down to medium and gently turn fish over using a fish spatula. Cook for an additional 4 - 5 minutes until fish is opaque and flesh is just beginning to separate.
Remove from heat and let fish rest for a few minutes while you finish the salsa.
Drain lime juice from onions, add onions to citrus. Mix to combine, add parsley and place on top of each piece of corvina. Serve immediately.