Apparently the Asian redtail catfish is a more aggressive catfish from a different genus,
Hemibagrus wyckioides, while the SA redtail is
Phractocephalus hemioliopterus. The Asian redtail is one of the most aggressive freshwater fish in the world, and you can't keep it with anything else, it will simply dismember it for fun. As for the SA, it is much more laid back and while it will eat anything that can fit in its mouth, it won't kill for fun. Also, SA redtails can be kept with proper tank mates and not bother them as long as they are of appropriate size.