Many Vieja are known to be fruit eaters, and highly vegetarian.
They will eat the fallen fruit, and if swallowed, the seeds pass thru the gut, and in this way the seeds are distributed, much in the same manner pacu will in the Amazon.
These would be tropical fruits that grow over water courses such as figs.
I had a Tilapia pond under a cherry tree, and never fed the Tilapia as they ate algae and any fallen, and rotting fruit throughout summer, when I cleaned out the pond in late fall, the bottom was filled with seeds.
I have also watched salt water fish come near shore, daily, to eat leaves and fruit from certain selected trees. Seems certain fish are attracted to only certain fruit species.

My bocourti, and former pearsei were ravenous, and indiscriminate leaf eaters.

dandelions before

after
