While in Long Beach, California we found Pier 76 Fish Grill. We had a favorable experience at this casual seafood restaurant for several reasons.
The Pier 76 menu has gluten-free labeling, and they have lots of g-f options - including all of their grilled fish. Also it's rare to find such high quality seafood for such a moderate price. The ambiance and location were nice - right in the center of downtown Long Beach. Overall this was a great find, and I highly recommend it.