Fisherman's port in Asuncion
there is a fisherman port near the city centre in Asuncion called "Varadero" in the Itápytápunta (red stone's hedge in Guarani) neighbourhood near the Hospital de Clinicas and the Medicine School, UNA.
In here, you can buy fresh fish daily or eat a typical pira caldo (fish soup) and other Paraguayan traditional food. Beware that there are not classy restaurants, but humble people offering their catch in their houses, the odd boat serving food and small bars serving beer and other drinks.
Check the viewpoint at Itapytapunta too for scenic views over the Paraguay River.
And if you feel unsafe around working class people, just forget about this tip!