Quite often our guests from US/ Europe have had their fill of meat by the time they come to us for lunch or dinner and ask for a fish option. Sushi is seldom mentioned though.
We have had quite a lot of success with La Pescadorita in Humboldt and Costa Rica. Its owned by the same guys as La Dorita - the Parilla chain - they have three or four dotted around town, I think.
Pescadorita does some decent fish dishes and will have a catch of the day. Risottos and Paellas are also on the menu.