A dark body covered in light spots is a common appearance in the genus, and it's not unlikely that some of these l-numbers may turn out to be the same species. L404 from Rio Tacutu and Rio Branco in the border area between Brazil and Guyana is another example, and most of all it looks like L136 from Rio Demini, an affluent of Rio Negro. These areas are known to share some similar types of fish, so there's a good possibility that L404 and L136 are populations of the same species. To tell them apart by looks is basically impossible, although it's worth noticing that L404 is usually always covered in small white spots, much like the L136a form. Rio Tacutu is a remote area with little ornamental fishing, so L404 is a very rare form in the hobby.
Name: Hypancistrus margaritatus (Tan & Armbruster, 2016)
Trade names: L404
Origin: Rio Tacutu, Rio Branco, Brazil
Maximum size: 15 cm / 6''
L404 needs an aquarium set up consisting of lots of hiding places in the form of rocks, wood and of course specially made caves that suit their measurements. In these the males will eventually guard their offspring. They prefer water that is fairly warm (27-30 C), soft and slightly acidic. Most of all it should be well oxygenated and clean, so a good filtration system and frequent water changes are essential. It's a rather small and timid species that should not be exposed to too much competition over food and shelter. Among themselves they are fairly peaceful, although males may quarrel for caves and females can sometimes be badly injured or even killed during the breeding-trapping in the male's cave.