Sorry to disagree, but it's not an Iridescent shark. I'm not familiar enough with the larger cats to be any help but I did have an IS at one point so I know this isn't one haha.
It's definitely not a Pangasius or Columbian. Was it wild caught? It does appear to be a native species, at least not something you'd see in your big chain stores. It will almost definitely get very large. And eat everything in your tank. Do you have a pond ready? It might be necessary.