Taxonomy & naming
The registry lists the fish as Hypancistrus sp. “L 401” and PlanetCatfish files it as Hypancistrus sp. (L401); neither names a related or same-fish code. Trade names on record are Hypancistrus sp. “Alenquer” and Yellow Zebra. L-numbers date from the DATZ system of 1988 for imported loricariids not yet identified, so an undescribed form carries no describing authority. The bibliography is brief: a care and breeding article on Hypancistrus sp. (L401), its title translating as care and breeding of a rare L-catfish in the aquarium, and an Aquarium Fachmagazin press review.
Morphology
About 4.5 in total length is the registry’s figure, and it offers no characters that identify L401 beyond that. Undescribed forms have no formal diagnosis. The trade name Yellow Zebra suggests yellowish banding, but it is a label rather than a described character. Listed as similar fishes are Hypancistrus seideli (L66 and L333), Hypancistrus sp. L270 (LDA76), L307 and L318.
Habitat
The registry places L401 in the Rio Curuá at Alenquer, Pará, Brazil, in the Amazon system that drains to the Atlantic in the north-east, and classes the water as clearwater. Neither substrate nor any microhabitat detail is recorded, and no sympatric fishes are listed. Loricariids of this kind generally live in clean, well-oxygenated, moving water with rock or wood for cover.
Feeding
The registry classes L401 as mainly an omnivore; whether it eats aquarium plants is not recorded. Omnivorous Hypancistrus in aquaria are usually given sinking pellets or wafers along with frozen foods and some vegetable matter. How the fish feeds in the Rio Curuá is undocumented, and the registry names only a dietary class, not particular foods.
Mating
The sexing note belongs to the genus, not to L401 alone: Hypancistrus males have a broader head, a slimmer waist, stronger pectoral-fin rays and more strongly developed odontodes. Spawning in Hypancistrus is typically in a cave, with the male guarding the eggs and larvae; the registry lists cave behaviour as the genus standard and gives no courtship detail for this code.
Breeding
The registry records that L401 has been bred in aquaria, though it gives no frequency, source or detail on individual spawnings. The only breeding literature it lists is the Hypancistrus sp. (L401) care and breeding article named above. Clutch size, egg numbers and fry development are not on record.
In the aquarium
The registry advises 77–84 °F, pH 5.5–7.0 and a recommended tank length of 31.5 in; this is aquarium guidance, not field measurement. Small groups are recommended, though one fish is possible. Genus-typical needs apply: well-oxygenated water with some current, a cave for each fish, and attention to territorial behaviour between pleco tankmates.
Conservation
L401 is Not Evaluated by the IUCN, since an undescribed form cannot be assessed. According to the registry it is on neither Brazil’s 2012 positive list nor its 2020 negative list. Collection for the trade and river engineering affect some L-number habitats in general; nothing specific is on record for the Rio Curuá.