Sunday dining in Madrid
What do people do for dinner in Madrid on Sunday evenings? It looks like most of the major restaurants are closed. Are tapas bars generally open?
A few tapas places around Santa Ana and Huertas are opened on Sunday nights. The touristy Botin is and the roasted meat are good. La Finca de Susana is inexpensive and lively but the food is nothing special.
I think most of us tend to eat a big late lunch on Sunday and just have a snack for dinner. In my neighborhood (La Latina) I think most of the tapas bars close in the late afternoon after the post-Rastro crush.
Since you are looking for a Sunday place and a seafood place, you might want to combine the two and check out Marisquería Rafa (near the Retiro):
If you do some googling, I'm sure you could find some reviews in English. You'll find simple, traditional sorts of preparations there with very good quality raw materials. It's still not cheap, but perhaps less expensive than the other marisquerías you are looking at.