This fish is probably one of the tank raised hybrid synos that are commonly being imported. It is neither S. angelicus, which is black with white spots, S. petricola, which has a vivid white leading fin edge on black fins, nor is it S. multipunctatus, which also has black finnage. The S. sp. (3) you found a picture of is probably as close as you're going to get to an actual classification for your fish, but you can also post the picture in the "what is my catfish" forum at planetcatfish.com for a more detailed description of why.
Barbie