There was a recent article in the New York Times that talked about cooking raw which means to cook meats or fish in lime juice. This concept is also seen in South America where people think that lime juice is strong enough to to kill bacteria.
There is a Latin American Dish called " Cerviche " which is made from fish or shell fish and it is only marinated in lime juice before it is consumed.
Lime Juice will not kill E. coli nor will it kill any parasites that may be in the fresh fish. If the fish has been commercially frozen at 0 or below for three days it may be safe.