The fishing in this province, like in most of the mountain areas, it is divided in lake fishing or reservoir and of river or stream. The first one that corresponds to all the lakes originated by other so many dikes has given place to a vertiginous development of the support infrastructure, with piers, boats, jetties, sale of sport articles together with elements for the nautical sports.
The most important lakes are those of Ullum, to 18 Km . of the capital and Los Cauquenes, in Jáchal, both offer very good possibilities of pejerreyes fishing of up to 2 Kg . and of yellow bagres (Pimelodus clarias) of up to 3 Kg ., species that has been introduced relatively little time ago and that it configures an attractiveness by itself, for the high quality of their meat, lacking the classic "flavor to mud" that usually offers in the River Plate, their origin place.
The fishing in rivers and streams is represented mainly by the salmónidos. Of them the most common is the trout rainbow and the most suitable rivers are the San Juan and the Castaño.
It is necessary to point out that a fishing reservation exists, only maybe in its gender, in charge of the Club of Hunt and Fishes of San Juan and that understands tracts of rivers Los Patos and Blanco until its respective ones nascent, divided in sectors. The interested ones in fishing will obtain the provincial permission of fishing and then the right to enter in the limit. It is only fished with spinning teams or of fly and it is absolutely forbidden the use of all type of natural bait. The limit is administered in similar form to that of the European fishing limits and the fisherman will register the entrance and exit of the place. The refuge Las Hornillas contain the basic services of the refuges of high mountain.