We had a Capybaras, at the wildlife compound my husband's family owned. It was big and very gentle. He kept it in a pen because as you might know they like swimming and can stay under water for up to five minutes. Since our lake had big alligators in it we could not allow it to roam free much. So it was a daily chore to cut fresh grass and gather pond weeds for it to eat.
It was friendly, like a huge guinea pig. But due to it's feeding habits and need for a bigger ranging area we passed it on to another wildlife rescue place that had large fenced in grassy areas and a safe fenced in pond. This place had some hippo's too, and it seemed they got on well together sharing the pond.