I believe it it to be L. Apurensis despite it's unusually dark pigmentation. without a clear profile shot and possible camera angle distortion it also does seem to have slimmer body proportions making me think it may be a male fish, even then an undersized specimen for it's age but then my fish was a female so no experience with a male of this species. Nothing else in the genera looks the same other than L. fowleri. As Viktor stated, the other species in the group like L. Nigricaudus (Guyana), L. Albomarginatus (Suriname) smallest, and L. Fowleri and L. Alexandri both from the Rio Sao Francisco in southern Brazil- banned from export for over a decade. Quick note: L. Alexandri still banned but recently L. Fowleri now permitted for export from Brazil! Anyway, I've talked with Jeff Rapps before he sold the store, much respect and trust for his knowledge so no doubt about the fish's origin. Most L. Apurensis come from Venezuela, The Apure and Orinoco River systems, Many tributaries of the Orinoco exist in northeastern Colombia so the species should be the same. Pseudopimelodid's are relatively easy to determine the sex, similar to sexing many synodontis', bagrid, ilacturids and others as well. First one must flip the fish over on it's back using net, Tupperware what have you, then closely observe the "naughty bits" or the ventral area, take a close up photo if possible. With male fish there will be a pointed V shaped genital papillae at the forward end of the orifice. In Females the genital papillae is usually smaller and rounded in shape rather than distinctly 'V' shaped. If I recall correctly, males typically have one orifice, female will have two, an anus and an oviduct at the forward position. To summarize, I think the fish in question is apurensis and not a batrochoglanis species, could it be some kind of rare, yet undescribed species? Possibly but very unlikely methinks. As Viktor suggested, not inclined to give up any organs anytime soon but would pay dearly and buy a new tank for a Lophiosilirus Albomarginatus...