Baryancistrus xanthellus L81 - Information

Taxonomy

Order: Siluriformes
Suborder: Loricarioidei
Family: Loricariidae
Subfamily: Hypostominae
Genus: Baryancistrus
Species: Baryancistrus xanthellus, Rapp Py-Daniel, Zuanon, & Ribeiro de Oliveira, 2011

Description

Baryancistrus xanthellus, also known in the hobby as Golden Nugget pleco, is a described species that is divided into numerous L-numbers such as L18, L85, L177, LDA60 and the L81. They are almost all found in the Rio Xingú in Brazil. The reason for the different L-numbers is the variety of patterns and colors that B. xanthellus can display.

The most important characteristic of B. xanthellus is its powerful, stocky build, which gives it a 'massive' appearance. It has noticeably small gill openings and a special membrane behind the last dorsal fin ray. In addition, it has more than 80 very small, closely spaced teeth (premaxillary teeth) on the anterior and most prominent bone of its upper jaw. This makes it an excellent 'grazer' for algae.
Baryancistrus xanthellus differs from its congeners by the presence of a broad light band on the margins of the dorsal and caudal fins, and by the unplated belly (as opposed to partially or completely plated in B. demantoides, B. longipinnis and B. niveatus).

Distinctive features of the L81:
The L81 differs from other Golden Nugget variants in two color-based features: the dot pattern and the ridges on the fins.

- The spot pattern: The orange-yellow spots on its body and fins are generally smaller in diameter. Consequently, they appear closer together or more spread out over the body (compared to B. xanthellus L177). There is less black space between the spots.
- The fin margin: The yellow or orange margin on the fins of the L81 is noticeably narrower. This broad margin is still present and bright yellow, but lacks the massive, wide margin of the Iriri-variant.

It grows to a fairly large fish of about 25 to 28 cm and has a fairly flat head.

Distribution and habitat

Baryancistrus xanthellus is found only in the Brazilian state of Pará, specifically in the Rio Xingú basin and its tributaries. The Rio Xingú is one of the largest and most ecologically unique tributaries of the Amazon River. This L81 variant is mainly found in the mainstream Xingú River itself, but is also found in tributaries within the basin. The Rio Xingú is a clear water river. Baryancistrus xanthellus is one of the most common pleco species in the Xingu River.

The riverbed of the Rio Xingú is composed mainly of dark volcanic rock, large boulders, and gravel. It is a warm and oxygen-rich river with clear water and strong currents. Water temperatures are consistently high, ranging from 29 °C to over 33 °C in the shallower sections. The water is soft and slightly acidic.

The L81 lives here among and under rocks in areas with strong to very strong currents and rapids. Young animals are often found closer to the banks where there is less current.

Baryancistrus xanthellus L81 shares its habitat with a wide variety of other Loricariidae, including species such as the Hypancistrus zebra L46, Scobinancistrus aureatus L14, Parancistrus nudiventris and other Baryancistrus-species.

Diet

Research with wild specimens shows that in the wild, this species primarily feeds on algae and biofilm growing on rocks. Algae, particularly filamentous algae like Spirogyra, and diatoms are common. Occasionally bryozoans and chironomid larvae (dancing midge larvae) were found.

However, when Baryancistrus species are imported, they are often malnourished and/or have health problems. Because they have a relatively high metabolism and constantly graze on biofilm in the wild, they are often emaciated and have a sunken belly upon import. Sometimes they also have a black belly, and in my experience, it's often impossible to get them to eat again in this critical condition.
This pleco species therefore often requires a longer quarantine period to acclimatize. As a result, they are not the easiest fish to keep, especially initially.

What do I feed my Baryancistrus xanthellus L81?

In the aquarium, it is important, especially in the beginning, to offer them several meals a day with varied food that mainly consists of vegetable material.

I feed my B. xanthellus mainly with EBO Spirulina paste (which I spread on a stone so they can graze naturally), EBO Spirulina soft granulate, and sometimes I alternate this with EBO Veggie sticks. As an extra vegetable, I give them zucchini, which they can also graze on.

Homemade recipes with gelatin, which consist of a mixture of pureed fish food, shellfish and vegetables, also seem to work well according to some keepers because the ingredients can be adjusted to your liking.

Aquarium

Minimum 120 - 150 cm in size.

Keeping this species at home isn't always easy due to its rather difficult feeding habits, especially during the initial acclimation phase. Therefore, it's not a beginner's fish.

Because Baryancistrus xanthellus grows quite large, it thrives best in a spacious aquarium with plenty of hiding places and possibly other peaceful fish. There should be sufficient breeding caves and/or hiding places in the aquarium.
They can be kept in a group, but keep in mind that adult males can be territorial towards each other and other fish.

The aquarium can be set up with a sandy substrate, smooth stones, breeding caves, and possibly driftwood.

These plecos are generally quite shy and dislike bright light. On the other hand, bright lighting can cause the growth of algae and spores in the aquarium, which the fish will graze on.

A good filter is also very important. This is because, as mentioned above, these fish naturally live in warm, fast-flowing water. Consequently, they always need clean water to stay healthy. Furthermore, they have a fast metabolism, which means the water becomes dirty more quickly. Weekly water changes are therefore essential.
Good surface flow/water movement or aeration is also essential, as this species requires a lot of oxygen.

Sex difference

Although this species is kept by many people, few hobbyists have a fully grown specimen at home. This is likely because almost 90% of these fish are imported and sold as very small specimens, and they also grow relatively slowly.
There are many questions about the sex of L81 or other B. xanthellus species online, but due to their generally small size, they cannot be properly sexed.

Unfortunately, I haven't yet found a pair to photograph the sex difference.

The sex difference is similar to Baryancistrus xanthellus L177.

Reproduction and breeding

Captive breeding has occurred only a few times so far. They lay their eggs in breeding caves, after which the male cares for the eggs and young.

Literature

Rapp Py-Daniel, L. H., Zuanon, J., & Ribeiro de Oliveira, R. (2011)
Two new ornamental loricariid catfishes of Baryancistrys from Rio Xingu drainage (Siluriformes: Hypostominae).
Neotropical Ichthyology, 9 (2): 241 - 252