Author: Darren Stevens
First published in Aquarium World May 2009

The genus Baryancistrus contains some of the most striking plecos in the hobby: including the gold nuggets, the snowflake pleco, and the magnum pleco. Bary means heavy in reference to Baryancistrusbeing more heavily built than Ancistrus.

There are 6 scientifically described Baryancistrus species, and a few more awaiting a scientific name.Baryancistrus can be separated from most other plecos by having a membrane that usually connects the dorsal (top) fin to the adipose fin (the small knob-like fin in front of the tail).

Baryancistrus are generally found in shallow fast flowing waters in the Rios (Rivers) Orinoco and Venturi in Venezuela; and the Rio Tocantins, Rio Tapajós, and the lower Amazon River system in Brazil. These fast flowing areas have a rocky bottom and plecos live in cracks in-between the rocks. The rocks are covered in aufwuchs – a German term for encrusting filamentous algae and the tiny animals living within it (such as insect larvae and small crustaceans).

Baryancistrus are specialised aufwuchs feeders. They have 4 large rasping plates (broad rows of teeth) for scraping this aquatic film, a very long intestine, and a small stomach to enable them to digest it. This is a difficult diet to imitate in an aquarium. Luckily they soon adapt to a variety of foods. They should be fed a largely vegetarian diet (algae wafers, courgette, cucumber, shelled peas, lettuce, spinach, etc) and occasional small quantities of high protein foods (blood worms, shrimps, tubifex, etc.). They are also thought to benefit from wood in their diet. As with Panaques, a high protein diet may result in the early death of your pleco.

These plecos are not for the faint hearted. They can be highly territorial and vicious when larger, particularly towards their own species, so be careful when introducing another one into your tank. Also keep an eye on a new Baryancistrus to ensure its getting enough to eat, as other fish can out-compete it for food.

Baryancistrus are slow growing; however most species can grow to 20+ cm, so they are not suitable for smaller tanks. As with most plecos they appreciate plenty of cover such as rocks and bogwood. They also require very clean water, and appreciate good water flow and lots of aeration.

Most species have not been breed in captivity. Gold nuggets (Baryancistrus xanthellus) have been bred occasionally overseas and the bluefin ‘Panaque’ (Baryancistrus beggini) has been bred once in New Zealand and occasionally overseas.

The following plecos are the most commonly available and recognisable Baryancistrus in New Zealand.

Gold nugget plecos (Baryancistrus xanthellus L018, L085, L177, andBaryancistrus species L081)

These stunning black plecos with gold spots and fin margins are justifiably amongst the most popular fancy plecos in the hobby. They require high quality water and plenty of cover and do well in pH’s of 6.5–7.4 and temperatures of 24–28°C.

There is one scientifically described species of gold nugget, Baryancistrus xanthellus, which includes two varieties: the regular “medium spot” gold nugget L18/L85, and the queen “large spot” gold nugget L177. The small spot or stardust gold nugget, Baryancistrus species L81 has the finest spots and has yet to be scientifically described. Gold nuggets are found in different areas of the Rio Xingú and one of its tributaries, the Rio Iriri, in Brazil.

Gold nugget pleco (Baryancistrus xanthellus L018, L085)

This is the commonly available gold nugget and has medium sized spots. This form of Baryancistrus xanthellus has two L-numbers because adult fish have less gold on the fin margins and numerous very small spots, and were originally thought to be a different form (L085). This gold nugget is found around Altamira on the Rio Xingú and grows to 35 cm standard length (tip of snout to the base of the tail fin).

Queen (“Big spot”) gold nugget pleco (Baryancistrus xanthellus L177)

The queen gold nugget is arguably the most attractive gold nugget. Unlike the more common L018/L085 variety, queen gold nuggets retain reasonably large spots as an adult. Queen gold nuggets are found in the Rio Iriri tributary of the Rio Xingú and grow to 20 cm standard length. They tends to have strongly coloured golden yellow spots and fin margins.

Stardust (“Small spot”) gold nugget pleco (Baryancistrus species L081)

This is the gold nugget with the fine spots. It is found in the lower Rio Xingú and grows to 18 cm standard length. This form tends to have paler yellow spots and fin margins.

Magnum pleco (Baryancistrus chrysolomus L047)

Magnum or mango plecos are a greenish to black medium sized pleco (to 28 cm standard length) with yellow to orange fin margins. They originate from the Rio Xingú in Brazil, and are suited to larger tanks with pH’s of 6.5–7.5 and temperatures of 26–29°C.

Snowflake pleco (Baryancistrus species L142, LDA33)

Snowflake or big white spot plecos are a black medium sized pleco (to 25 cm standard length) with large white spots. They originate from the Rio Tapajós rapids in Brazil, and are suited to larger tanks with pH’s of 6.0–7.4 and temperatures of 24–28°C

Blue-fin Panaque (Baryancistrus beggini, L239)

Blue-fin or blue Panaques are a small (to 12cm SL) black pleco with a blue sheen and often an ice blue coloured edge to the dorsal (top) and tail fin. They originate from the Rio Orinoco drainage in Venezuela, and are suited to medium sized tanks with pH’s of 5.5–7.5 and temperatures of 23–29°C. Prior to being scientifically named in 2009, this species was often placed in the genus Ancistrini. They were recently bred in New Zealand (see Planet Catfish Shane’s World article).

There are other Baryancistrus that are occasionally imported including Baryancistrus niveatus (L026) and the hi-fin green phantom pleco (L200). Green phantom plecos comprise two very similar looking species: the hi-fin ‘Baryancistrus‘ demantoides and Hemiancistrus subviridis. Hi-fin green phantoms (B. demantoides) don’t fit well into Baryancistrus and may belong in another Genus. Hemiancistrus subviridiswill be covered in another article.

Two other Rio Xingú plecos are sometimes wrongly called “flathead gold nuggets”: Hopliancistrus species L017 and Pseudancistrus asurini (L067). These two species are more slender than gold nuggets but they are covered in fine yellow spots and have a yellow margin to their dorsal fins, although only P. asurini(L067) has yellow on the dorsal fin margin.

I would like to thank Firenzenz and Krazy Geoff for their comments and improvements on earlier versions of this article, Rabbit for pointing out the finer points of separating out the gold nuggets, and the Pet Centre, Lower Hutt, for allowing me to photograph their blue-fin Panaque.

References:
Planet catfish www.planetcatfish.com
Lujan, N.K.; Arce, M.; , JonathanW. Armbruster, J.W. (2009). A New Black Baryancistrus with Blue Sheen from the Upper Orinoco (Siluriformes: Loricariidae). Copeia 2009: 50–56.
Py-Daniel1, L.R.; Zuanon, J.; de Oliveira, R.R. (2011). Two new ornamental loricariid catfishes ofBaryancistrus from rio Xingu drainage (Siluriformes: Hypostominae). Neotropical Ichthyology 9: 241–252.
Silva, G.S.C., Roxo, F.F. and Oliveira, C. (2015). Two new species of Pseudancistrus (Siluriformes, Loricariidae) from the Amazon basin, northern Brazil. ZooKeys 482: 21–34.
Vires, L. (1999). Loricariidae: The Tricks of the Trade. Vires Publishing.

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