Nannoptopoma

Sold as an otocinclus far more often than under its own name, and the confusion has a taxonomic root: Scott Schaefer erected the genus Nannoptopoma in 1996 around Otocinclus spectabilis, so this fish spent its earlier career inside the genus hobbyists already knew. FishBase records a maximum standard length of 3.3 cm, small even by suckermouth catfish standards.

Identification is a plate-counting job rather than a colour one. Schaefer separated the genus on the pattern of abdominal plating, a pair of slender plates behind the coracoids followed by one to three unpaired plates down the midline, and on a coracoid process that curves hard enough for its tip to point upward. Against its only congener, N. spectabile, this species carries thoracic plates, 21 to 22 lateral plates and 21 to 37 teeth on the dentary. The body is elongate and the fin count modest: one dorsal spine, seven dorsal rays, six anal rays, 26 vertebrae.

In the wild it is a bottom-hugging freshwater fish of tributaries feeding the upper Amazon in Ecuador and Peru, and of the central Amazon and upper Madeira in Bolivia and Peru. IUCN assessed it as Least Concern in 2020, and it carries no commercial fishery pressure.

What no authority publishes is a care sheet. Neither FishBase nor Seriously Fish prints a temperature range, a hardness figure or an aquarium volume for the species, and this page leaves those fields empty rather than borrowing them from a related genus and presenting a guess as data. The one usable hint is the estimated trophic level of 2.4, which puts it with the aufwuchs grazers: a mature tank with algae-filmed surfaces feeds it in a way a newly set-up one does not.