Hi all,
I think all the little Hisonotus and Parotocinclus spp. would be hard to keep unless you could find captive raised stock, they would have hardly any chance of surviving being caught and shipped intact. I think this is also the problem with Otocinclus cocama. Like Garuf said none of these have L numbers.
Parotocinclus jumbo is definitely hardier, and had an LDA number "LDA 25", but it doesn't have red fins. Some of the Chaetosoma spp. look similar, have an L. number and have reddish fins, so it may have been one of them.
cheers Darrel