Be sure to visit a market as these are amazing.
Usually in the middle of the market you will find the fish section with fish you may never have seen before.
Our local market on Travessera de Gràcia 186:
Mercado De La Boqueria on La Rambla 89:
Mercat de Santa Caterina on Avenida Francesc Cambó 16:
Nice bar and great tapas at reasonable prices.
Calle Abaixadors 10, El Borne
Great traditional taverna serving pinchos the traditional small bread with sticks. You pay by the stick so all pieces are the same price. Current price is €2 per stick. They also have a restaurant in the back.