Tapas, everybody has heard of tapas, but what exactly is a tapa? A tapa is a small portion of food that you get when ordering a drink, normally beer or wine. Depending on the bar, it can vary from peanuts to Spanish omelet or even a small portion of paella.
In some parts of Spain (e.g. Granada and Leon), the tapa is free. Unfortunately, this is not the case of Barcelona where you have to pay for them. Source: tourisminbarcelona

Cal Pep is one of the most know tapas restaurant in Barcelona. Its reputation goes largely behind the city wall and it’s justified.. Everything is fresh and fun, the tapas, the people, the service, the wine.. Nothing to say just that you have to be there once otherwise you don’t know what tapas are. While waiting look the orders and make your menu.
Every meal is a delight and every season a new pleasure that follows the market arrivals.. There is also the restaurant “Cal Pep” next door with notorious fish and seafood dishes as well. Both are crowded, book, book, book at the restaurant or be patient at the bar but go there… Source: barcelona

We believe that “Els Pescadors” is one of the finest fish restaurants in Barcelona. Located quite far from the center, in Poble Nou, it worth go there. First for the place on a little square with trees, very pleasant.
Then for the dishes, mostly fishes, every plate is a delight try: calamares, gambas, arroz, Suquet dels pescadors, Angler fish fricandó, Tuna with pickled Figueres onions, Hake with romesco bread and leek mousseline sauce…A great contemporary cooking.. Perfect to invite your best friends. Source: barcelona

On the seafront in the Barceloneta area, Can Majo is one of the greatest fish restaurant of Barcelona. We like in this well decorated place to start by sharing tapas of shellfish, then it’s quite difficult to choose between the excellent paellas, the fideus…Our favourite is the rice with losbter (take this one if it is difficult for you to choose)… You can try fish of course they are all perfect, and only if you are very hungry taste the traditional Suquet (a pan of monkfish, hake, mussels, clams, prawns and potatoes). Very kind and thoughtful service. In summer, book your table on the terrasse. Source: barcelona