Taxonomy & naming
L097 is a DATZ L-number, a label for an imported suckermouth catfish that could not be named when it arrived, so it has no describing authority and no type specimens. The registry lists it as Pseudacanthicus sp. "L 97", with no cf. or aff. comparison; PlanetCatfish files it as Pseudacanthicus sp. (L097). Trade names on record are polka dot cactus pleco, King of Galaxy and, in German, Gelbflecken-Kaktuswels (yellow-spot cactus catfish). Similar catfishes named are L65, L282, L520 (queried as possibly identical), L452 and Pseudacanthicus fordii. The bibliography cites the Welsatlas 2 (2005), Seidel's Back to Nature handbook (2008) and the Miniatlas L-Welse (2005).
Morphology
About 8 in total length, by the registry's figure. The trade names point to a spotted pattern — polka dot in English, Gelbflecken (yellow spots) in German — but no description of the markings is given, so the diagnostic characters are not on record. Structurally it is a Pseudacanthicus, a suckermouth catfish armoured in bony plates carrying odontodes.
Habitat
L097 comes from the Rio Tapajós near Santarém, Pará state, Brazil, in the Amazon system; the registry classes the water as clearwater. Habitat place, substrate, depth and current are not recorded. The temperature and pH figures are aquarium keeping ranges, so no field water chemistry is on record for the locality.
Feeding
Registry data describe a predominantly carnivorous fish that does not eat plants. In the aquarium that means meaty sinking foods, such as frozen mussel, prawn and large bloodworm, along with sinking carnivore pellets. Its natural diet in the Tapajós is unrecorded, so the diet class is the only guide, and offering some variety within it is the usual practice.
Mating
Sexing guidance is genus-level, not specific to L097: in Pseudacanthicus the male has a longer, broader head, is often more attractively coloured and often has a larger dorsal fin. The genus typically spawns in caves, the male guarding eggs and larvae there. No courtship behaviour has been described for L097 itself.
Breeding
Captive breeding of L097 has been reported, with welse.ch cited as the source. The bibliography also includes an article by Udo Wanninger on the first breeding of the cactus catfish L97. No clutch size or fry development is given, so the details of the spawnings are not on record. The registry lists known hybrids with Pseudacanthicus leopardus, P. cf. leopardus L427, P. nyktos (L185), P. pirarara (L25) and P. cf. spinosus L160.
In the aquarium
Small groups are the registry's advice for L097, though a single fish is possible. Its keeping range is 79–86 °F and pH 5–7, with a recommended tank at least 59 in long; these figures are aquarium guidance, not field measurements. As in other Pseudacanthicus, expect to provide clean, well-oxygenated water with current and rock or wood caves. Territorial behaviour toward other plecos is common.
Conservation
According to the registry, L097 is on Brazil's 2012 positive list of species cleared for ornamental export and not on the 2020 negative list. The IUCN Red List has not evaluated it, since an undescribed form cannot be assessed until it has a name. Its wild population is unknown; collection for the trade and river engineering affect some L-number habitats in general.