L401 is very similar to L333 from Rio Xingu, and to tell them apart can be really challenging. In other words, if you are presented with captive bred strains of L401 or L333, you may have trouble telling which one it is just by looking at them. So, one must simply trust the breeder or the trader. If you compare wild specimens, L401 will appear slightly flatter in it's shape, and has slightly smaller eyes than L333. Also, most suppliers in Brazil will be able to tell you if the fish in question was collected in Rio Xingu (L333) or Rio Curua (L401). The fact that both L333 and L401 are found near the mouth of the rivers they occur in where these meets the Amazon main channel makes me believe that they are possibly different populations of the same species.
Name: Hypancistrus sp. “L401”
Trade names: L401, L333 “New Alenquer”
Origin: Rio Curuá, Brazil.
Maximum size: 14 cm / 6''
L401 is very similar to L333 from Rio Xingu, and I still haven't been able to find a way to tell them apart other than by location. In other words, if you are presented with captive bred strains of L401 or L333, you will probably not be able to tell which one it is just by looking at them. So, one must simply trust the breeder or the trader. The fact that both L333 and L401 are found near the mouth of the rivers they occur in where these meets the Amazon main channel makes me believe that they are simply different populations of the same species.
In young fish, the pattern of L401 can be very striking, with just a few, broad, black lines aginst a very light, golden body. Some individuals show a mutated pattern of just a few black lines. Adult specimens, males in particular, can become very grey and dull coloured with their body almost covered in odontodes.
They need 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. 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. Males develop longer odontodes on their pectoral fins and on their cheeks, and have broader heads. Hypancistrus are mostly carnivorous, so a selection of crustaceans, insect larvae and fish meat should be offered along with high quality dried foods that also contain some vegetable matter.