If you went to see the fountains, tonight we recommend dinner at a very authentic restaurant, Pulpería A'Gudiña. Amazing pulpo a la gallega (Galician octopus, 11.40€), pimientos de padrón (small green peppers, 4.60€), pescadito frio (fried fish, 4.90€) and chipirones firtos (fried baby squid, 5.50€). Accompany the meal with a bottle of the house white wine (6.40€). The restaurant is just a 10 minute walk from the fountains. Take Avinguda de Rius y Taulet towards Avinguda Parallel, turn left at Carrer de Lleida, right at Carrer de Tamarit, and walk to Avinguda Parallel. The restaurant is on the corner you can see crossing the avenue.
If you do not fancy fish, walk 10 minutes more for the Avinguda Parallel to the sea, and, climbing to the right along Carrer Margarit, you will find the Bella Napoli (carrer Margarit 14), one of most famous italian's restaurant in Barcelona. Their pizzas are spectacular (9-11 €) not to mention the chef penne (10 €). Best book in the 93 442 50 56 or it will a tough job to find a table.