I have been staying in a flat near to La Pescaderia and finally decided to visit it based on reviews here and elsewhere. The restaurant appears to only be open for lunch (since I walked past it many evenings and it was closed). I was given a menu in English/Spanish (the Spanish version was much more accurate!) when I sat down. The ambience is lacking. When I was there, there were a host of familes with crying babies, etc. but not the fault of the restaurant.
The waiter asked me what I wanted and recommended a dish of the day, which I accepted. It was a mix of several types of fish, but the quality was very poor. It was if the waiters were told to "sell" the dish of the day. It tasted as if it were microwaved.
For the main course, I had a shrimp platter, the quality was fair, but the presentation was not. I had to use my hands to peel the outer layer from the food, which was awkward. I would recommend they serve any shrimp dishes in a way that they are more easily eatable.
Overall, I wouldn't give the place a high rating. The service appeared to be compulsory, the food was adequate but lacking and the price was a bit high.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.