Taxonomy & naming
The L-Wels registry carries three entries for L136: Hypancistrus sp. "L 136" and the combined listings "L 136" / "LDA 5" and "L 136" / "LDA 6". That ties two further code numbers, LDA 5 and LDA 6, to this fish. L136 itself comes from the L-number system that DATZ began in 1988; it is a trade label with no authority and no type specimens behind it. PlanetCatfish treats L136A and L136B as the same fish, and a variant label "L 136c" appears among the trade names. The German trade name is Demini-Engelsharnischwels (Demini angel armoured catfish). Literature listed by the registry includes Seidel's Hypancistrus Fibel (2010), Andreas Tanke's article on armoured catfishes from Roraima and a 2016 DATZ catfish press review.
Morphology
About 4.5 in total length is the registry's figure for L136. Colour, pattern and other diagnostic characters are not described. The registry lists as similar its own L136 / LDA 5 and L136 / LDA 6 entries, Hypancistrus margaritatus (L404) and Hypancistrus sp. L489 — comparisons made by the registry, not statements that L136 is any of them. Like other loricariids it is armoured with bony plates, with small tooth-like odontodes on the plates and fins.
Habitat
The registry's locality for L136 is the Rio Demini in the middle Rio Negro drainage, Amazonas state, Brazil, and the water is classed as clearwater. No habitat place or substrate is given, and depth, current and field water measurements are all unrecorded. The Demini locality and the clearwater type are the whole of the wild-habitat record for this form.
Feeding
The registry's diet class for L136 is omnivore, and in captivity it is fed as one; whether it eats aquarium plants is not recorded. Sinking pellets or wafers make a base, with frozen foods such as mosquito larvae and some vegetables alongside. The wild diet of the Demini fish is unrecorded, so these are aquarium suggestions drawn from the class and not field observations.
Mating
The registry's sexing note is genus-level: Hypancistrus males have a broader head, a slimmer waist, stronger pectoral-fin rays and more strongly developed odontodes. Nothing is recorded about how L136 itself courts or pairs. Hypancistrus are cave spawners in which the male guards the eggs and larvae, and the registry marks caves as standard for the genus; that is the typical pattern, not an observation of this code.
Breeding
The registry records repeated aquarium breeding of L136 and adds a known hybrid with Hypancistrus sp. L411. No source or figures are given. Clutch size, incubation time and fry development are unrecorded for L136 itself, which leaves only the genus-typical outline: cave spawning, with the male guarding the eggs and larvae.
In the aquarium
Registry guidance puts L136 at 79–84 °F and pH 5.5–7.5 in a tank with a recommended length of 31.5 in. These are aquarium figures, not field measurements. Keeping in small groups is recommended, and a single fish is possible. Hypancistrus do well in clean, well-oxygenated water with a current and caves or rock cover. Territorial behaviour toward other plecos is common.
Conservation
The IUCN Red List has no assessment for L136 (Not Evaluated); an undescribed form cannot be assessed until it has a name. The registry records it as not on Brazil's 2012 positive list and not on Brazil's 2020 negative list. Population size and threats are unrecorded for this form. In general, collection for the trade and river engineering affect the habitats of some L-number fishes.