Catfish of the Month Right December 2000

Baryancistrus xanthellus
L018, L081, L085, L177, LDA060, LDA116, LDA117, Gold Nugget Pleco, Guldklump-sugemalle (Denmark) - Baryancistrus xanthellus   Rapp Py-Daniel, Zuanon & de Oliveira, 2011

Article © Julian Dignall, uploaded December 01, 2000.

Editor's Note. This species is was described in 2011 as Baryancistrus xanthellus. While the l-number discussion below is more or less obsolete, I've left it unaltered as it was written some eleven years before the description and still holds up quite well! It is also both interesting and useful to see where we've come over the years too.

X marks the spot where collectors struck gold! The problem, if you could call it that, with the maps below is that there is more than one "X". There are in fact 3, this is because there are at least three gold nugget plecos. Oh, and they have 4 "L" numbers among them too.

Maps of South America
Map of South America Map of Brazil Map of Para State, Brazil
X = L81, X = L177 and X = L18 & L85

Although X marks the spot each one is between 80 and 100 miles away from its nearest neighbour. Perhaps "X" is for the Rio Xingu rather than precise locations! Anyway, L18, L81, L85 and L177 are all gold nugget plecos. The table below will hopefully help with identification. What you have to bear in mind is that the comparisons are only really useful when comparing similarly sized fish and that individuals patterning is very variable anyway. Aqualog's original Loricariidae - All "L" numbers actually has a good trio of pictures showing juvenile, sub-adult and adult of L18/L81. Look up L85 for these pictures. It should be noted that the pictures in Aqualog for all these L-numbers are accurate and good representations of the original fish. Alright so far, but what are the factors that differentiate these fish? The following table should help.

L-Number Image Narrative
L018 Baryancistrus sp. This is the "common" gold nugget with medium sized spots. This is a picture of a juvenile. L018 is found in area around Altamira on the Rio Xingu. This is about 75 miles downstream (North) of where the Rio Iriri joins the Rio Xingu.
L081 Baryancistrus sp. This is the small spot gold nugget from the lower Rio Xingu. The yellow colouration on this fish (spots and fin seams) tends to be paler. This is a picture of a young sub-adult.
L085 Baryancistrus sp. These are adult L18, they are one and the same fish. The adult colouration is markedly different however. This is a picture of an adult male.
L177 Baryancistrus sp. This is the big spot gold nugget from the Rio Iriri tributary. The yellow colouration on this fish (spots and fin seams) tends to be a stronger yellow. This is a picture of a juvenile. Arguably the most cosmetically pleasing of the gold nugget tribe.

This all seems relatively straightforward, Corydoras keepers have been doing this sort of thing for years, right? Well, not exactly. The individual fish can also change colour - exactly the same fish as pictured on a dark piece of wood against a light background will look very different seconds later because it is now sitting on lighter gravel out in the open. With identification being such a fraught, tentative process, it is perhaps reassuring to know that care of all of these fish is somewhat simpler if not less demanding.

Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

Down Cat-eLog Data Sheet
Scientific Name Baryancistrus xanthellus  Rapp Py-Daniel, Zuanon & de Oliveira, 2011
Common Names L018, Gold Nugget Pleco
L081, L085, L177, LDA060, LDA116, LDA117, Guldklump-sugemalle (Denmark)
Type Locality Rio Xingú, in the vicinity of the cachoeira Buraco do Inferno, 3°27'07"S, 51°41'53"W, Senador José Porfirio, Pará, Brazil.
Pronunciation bah ree ann siss truss
Etymology Greek, barys = heavy + Greek, agkistron = hook - Essentially "Heavy Ancistrus". From the Greek xanthellus, yellow, in allusion to the bright color of the specimens.
Article Link - Shane's World Right Catfishology Right The yellow seamed “Golden Nugget” – a problem pleco?
Down Species Information
Size 240mm or 9.4" SL. Find near, nearer or same sized spp.
Identification The combination of yellow markings on the dorsal and caudal fin and numerous yellow spots on the body is specific to this species. L081 (not mentioned in the description of B. xanthellus) is a fine spotted colour form with a dark base colour. L177 is a variety with larger spots more obvious in younger specimens and LDA060 is a variety with ill-formed spots or flakes. All are main channel fishes. After the description of the species in 2011, Aqualog added LDA116 and LDA117 both from the river around Sao Felix do Xingu. LDA116 is a paler colour form with faded almost invisible fine spots. Juveniles show a thin dorsal yellow seam and a little more yellow at the edge of the caudal which it keeps into adulthood. LDA117, by contrast, has a lot of yellow in these fins - about one-third yellow in the dorsal and the caudal fin is about half yellow. The spots are medium-sized and dense. However, adults lose all bright yellow spots and seams with the spots fading to small indistinct marks.
Sexing Dimorphism is difficult to notice unless the fish are at full breeding size. Males have a flatter, more levelled slope to their foreheads and are slightly wider about the head. Females have a more rounded forehead and are slightly plumper at the mid body when in spawning condition. There is no noticeable difference in odontodal growth in either gender.
General Remarks The common name came from residents of Altamira and the surrounding area who used to work in gold mining in the river (and hence were used to precarious diving for work). When mining there died out in the 1980s, they found a new source of income from collecting "Acari-Gold" - the Xingu's omnipresent Gold Nugget Pleco.
Down Habitat Information
Distribution This species is widespread and common in the Rio Xingu. Exports are collected near Altamira, from the area called Volta Grande do rio Xingu, an area immediately above Belo Monte falls, and from rio Iriri, the larger tributary of rio Xingu. L177 is from further upstream near the where the Rio Iriri joins the Xingu. L081 is reported in DATZ to represent three very similar small spotted gold nugget plecos. It was said to be hard to keep alive for any length of time; the others are considerably more hardy - however as more is known this appears more to be a result of transit times. These fish all represent the range of population, as more and more areas are collected, there seems to be a little pattern to the matching of colour form to geographic location.
Amazon, Lower Amazon, Xingu, Lower Xingu (click on these areas to find other species found there)
Amazon, Lower Amazon, Xingu, Iriri (click on these areas to find other species found there)

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IUCN Red List Category Near Threatened, range map and more is available on the IUCN species page. Last assessed 2018.
pH 6.4 - 7.6
Temperature 25.0-30.0°C or 77-86°F (Show species within this range)
Other Parameters Clear with a noticeable current.
Down Husbandry Information
Feeding These fish are grazers, but not in the sense that they eat only vegetation. They actually sift and chew at the film of organic matter on hard surfaces in search of higher protein foods. In the wild this would constitute mainly of algae and vegetable matter, but with a variety of foods from small insect larvae and crustaceans to other animals eggs. With this in mind, a largely vegetarian diet, cucumber and courgette appear on the accepted menu, with treats of frozen foods such as bloodworm and blackworm, along with frozen prawns. Algae and plants are avoided. Accepted food morsel size changes with age in all of these fish. Best results are obtained by offer these foods in a paste. The very long intestine of these fishes indicates a biology adapted to breaking down food high in vegetable content. User data.
Furniture Bogwood and rock caves. Plants are up to you but won't be molested by the fish.
Compatibility Gold nuggets are territorial to other bottom dwellers and downright vicious to other gold nuggets. This stems from a desire to find and defend the best spawning cave, so take this into account if you plan to introduce these fish into a catfish tank. They do well in a community environment that fits their other requirements. Be careful with adult fish, they can kill each other in a crowded space.
Suggested Tankmates Although strong currents are needed for breeding attempts, only good water quality and a high temperature are required for this fishes successful onward maintenance. Thus, characins are good biotope fish but you could look further afield at discus and gouramis. Most other cichlids tend to over compete for food with these fish, so be careful especially when introducing new gold nuggets.
Breeding Well documented breeding in captivity has been accomplished twice. The fishes had a very specialised diet of blended meat, fish and vegetables and were kept in a large aquarium with lots of current, high DO and spawned at 30°C. The free-swimming fry were fed the same food to raise them.
Breeding Reports There are 2 breeding reports, read them all here.
Down Further Information
Reference Neotropical Ichthyology v. 9 (no. 2), pp 242, Figs. 1-2.
Registered Keepers There are 594 registered keepers, view all "my cats" data.
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Last Update 2022 Oct 03 01:58 (species record created: 2000 Dec 01 11:22)

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