Ps :The old River Dolphin tank was much bigger than it appeared on Pictures-nevertheless it was too small for that species from our todays view, but unless that fact they were doing very well in it. I have Pictures of the old pool in its full size, but I don't upload my own Pictures-Sorry.
According to the information on Zootierliste and on the link below (in German) they imported 3.2 wild caught animals from Venezuela in 1975. Both females and one male died within the first few years, the oldest of the surviving males in 2006, not that long after moving into the current exhibit.
