Downstream the Yacyretá dam one can find pacú, a species that is very hard to catch. Its maximum weight is 10 kg. Pieces that may be caught could weigh from 2 to 3 kg. An omnivore, the pacú feeds, at certain times during the year and under certain conditions, exclusively on the fruits of trees and plants growing on the shore. The challenge for fly-fishing is to cast beneath the trees, trying to imitate falling fruit, so that a specimen will emerge from the water and snap at the fly with confidence.