Too many to name. I'm aware that it has sort of become a dumping ground for most of the 'additional' large fish in the collection. Of course there are the ubiquitous ones like redtail cats, pacus / tambaqui, fei feng, kong ming, etc.
I remember a few medium motoro rays in the past too, but those have most likely been transferred to either the River Safari / Fragile Forest.
Always found it humorous that the manatees were introduced there, considering it was historically an ornamental koi pond during the 2000s.
Friends and I joked that river dolphins or possibly even an Orca calf would replace them once they were gone.