I'm 99% sure the fish isn't a hybrid. If it was captive bred, maybe, but as far as I know, there is no captive breeding effort of ANY Chaetostoma other than some rare occurences of "accidental spawns". Given the chances of also having a set of mismatched species in the pair that spawnes, it is extremely unlikely it's a man-made hybrid - and hybrids are really quite rare in nature [especially amongst fish that do not travel very far in general].
We certainly do not have all
species in the Cat-eLog. There are 35 species in the Cat-eLog. Fishbase lists 45 valid species, and the Cat-eLog has several undescribed/unidentified species, so we're missing a lot more than 10.
All of these fish are superficially pretty similar, and it is far from easy to identify them. There are however only a few species that are frequently exported. One of those is the C. sp(1).
I'm pretty sure this is a correct ID - the size and number of spots will indeed vary depending on several factors, such as fish size/age as well as individual differences.
If you look at the pictures in the Cat-eLog, you will find quite a few different variations on spots, and I don't think Chrisinha's fish are outside the range of variation that one can expect.
So, in my amateur opinion, the id by Silurus is correct. Silurus, although not infallible, is a professional fish expert - he works in Singapore at the Raffles Institute, and is the author of scientific descriptions of several dozen species, many of which are catfish. He studied in Michigan, and as far as I understand, spent quite some time "studying" the fish available in fish-stores in America.
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Mats