This legendary local institution is the place for river fish, on the costanera 6km north of downtown. There are few frills and no choice: four or five courses of delicious surubí, sábalo or pacú are brought out, and you can repeat as often as you want. Drinks are extra but cheap.
It’s around AR$160 each way in a taxi (staff will phone one to take you back) or catch bus 16 from any point on the waterfront road.