When not by the sea we found a great substitute for corvina.
2-3 lbs of orange roughy (this is an excellent white fish)
1 large onion
4-5 aji chombo (when not available I use pickled hot peppers)
1 8oz bottle of lemon juice (if you have fresh limes and lemons its better)
1 8oz bottle of lime juice
salt and pepper

Chop up fish into small bite size pieces. Dice onions . Chop peppers.Put in
in GLASS container. Cover with juices,couple shakes of salt and pepper.
Cover (saran wrap) and marinate for 12-24 hours in refrigerator, stirring
occasionally. Serve with saltine crackers, topped with hot sauce.