Yes, this is Hydrolycus tatauaia, not H. armatus. In reference to the "special sub" in the OP, he was referring to sub-species, not sub-strate. Regardless, the dealer is clearly one of two things, an amateur when it comes to fish identification, or a vendor willingly trying to sell tats as armatus. Either way, I'm not sure if that's the place I'd be giving my hard earned cash.
Haha you might be right about the intended meaning of "sub".@op, tat's are very nice fish. Very pretty, esp once the tail reddens up some more. Did you happen to see which country in south america it was imported from? I'd be willing to bet Peru.
