As a part of his PhD dissertation in ichthyology, Racoll (Rupert A. Collins) has studied DNA of many commercially available syno hybrids in an attempt to pin down their parentage. You can trust his opinion when he says hybrid #9 (same as in my first link).
Take a look at this
http://www.planetcatfish.com/forum/viewtopic.php?f=13&t=38389&p=262987 It is about the same hybrid syno as yours and has more interesting info. Rupert's looked at mitochondrial DNA of this hybrid and is sure the mother species is Synodontis decorus. To pin down the paternal side appears harder and this part he has not finished.
