Help with Oto ID + request for info...

Can anyone ID what species of Oto this is?

http://mikes-machine.mine.nu/Otocinc...s_DSCN5429.jpg

As is evident from the name my best guess is O. affinis.
I don't think it's vittatus because, well, it doesn't look like the
vittatus on FishBase, and doesn't fit with the descriptions I've read
of vittatus.

But it could be a vittatus anyway, I guess. There's several other
possibilities too, e.g. O. vestitus, and probably others I don't know
of.

The size of the fish in the photo is approx. 30 mm.

Also, I'm curious if the Otocinclus you seen in shops are normally
wild-caught, or if they are farm-raised?