So, I couldn't get a clear enough pic of him during the move either, he just didn't want to stay still. However, I think I have a positive ID on him.
I was at the lfs the other day and seen a heap of catfish that look just like Felix, I asked the guy if he know what they were, he told me nigriventris. I asked him how he could be so sure and he said... HE BREEDS THEM!!! Every fish in that tank was offspring from his USD cats. I asked him why they look different to other nigriventris and he said they were a "zebra kudu" or "kutu" variant or something like that, which is apparently more popular down here or something.. I also asked if he'd be nice enough to come round and help me ID mine, he was, and he confirmed that I had exactly that.. He also told me that if I can get a bigger tank for them, that he would swap me out a few more juvie USD cats for my next brood of silver dollar eggs, which is fine by me, I normally let the corydoras eat their eggs coz I can't be bothered with fry. So, yeah, things seem to be looking pretty awesome right now. I'll continue trying for a video (these end up clearer than pics) just to confirm again, but I trust the blokes knowledge on catfish of any kind, and if he breeds them to sell, I assume he must have a decent idea what he's talking about.