Whooo! Been fishing at Rietvlei since I was a laaitie!
There are MASSIVE carp, and Black Bass.
We never had any major success, besides looking at the more professional anglers' near us bagging stuff.
The dam's water is very clear, so you can sometimes see the fish...and become frustrated!
As a student we went there once or twice and caught little kurper while sitting in the water (It was a hot day) and making a competition out of it! It didn't end well, but there we go!
The Northernmost end is shallow, so pro bass fishermen can wade about. We encountered my English professor there one Sunday afternoon, I remember it well.
He had had bad experiences with my entire family over the years, socially and educationally...but took it all in good spirit!