The popular plecos

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Do you have a favourite catfish? If not, then it’s high time you considered the small and charming Hypancistrus, writes new contributor Haakon Haagenson.

Back in the early 1980s, fishkeepers were not blessed with a wide selection of plecos to choose from in the aquarium trade. Little did they know that this was about to change drastically, and by the end of the decade major German importers were presenting new and exciting findings on a regular basis. 

Identifying all of these new plecos was not always easy, as they were typically not possible to assign to any of the known, scientifically described species. Because of this, the Germans decided to label them with numbers instead of creative and catchy names, and hence the L-number system was established. If you’ve ever wondered, the ‘L’ stands for Loricariidae, the family to which these catfishes belong.

Among all the new types coming in were some notably striking ones, such as a small, zebra-striped pleco from Brazil. The fish was found by some Japanese fish collectors in the Rio Xingu, and when seen by hobbyists it immediately caused a stir. Only a couple of years later it was scientifically described by the ichthyologists Isaac J. Isbrücker and Han Nijssen as Hypancistrus zebra, though it often still endures in the public mindset as L046.

During the 20-year period following from 1990, the interest in L-number plecos peaked. By the end of 2010, over 450 L-numbers had been assigned. Among these were a good number of Hypancistrus, which had established themselves as the most popular representatives of plecos for several reasons. Many of them are mainstays in the hobby, and although the interest and hype surrounding L-numbers may have dwindled during the last 10 years, they still have a great many fans in the fishkeeping community. 

Luckily, fishkeeping is still very much a thing, and with new recruits coming in it might be nice to give a fresh presentation of what Hypancistrus are. The purpose of this article is to give a brief introduction to these particular species and also give an insight to how to best take care of them in captivity.

What and where?

‘Hypo’ is a Greek term that means ‘less than,’ and this is a reference to the teeth — Hypancistrus have less teeth than Ancistrus. They reason for their low number of teeth is dietary, something I’ll return to later. 

There are about 50 or so known forms of Hypancistrus, and of these there are currently eight scientifically described species. they are small, only ranging from 6-20 cm long, with characteristic ‘sucker mouths’ and they often display a contrast-rich pattern of stripes or spots. 

Hypancistrus are naturally found in tributaries to the Orinoco system in Colombia and Venezuela, and in affluents to the Amazon in Brazil.
No Hypancistrus have yet been found in Ecuador, Peru, Suriname, French Guyana or south of Brazil. They are mostly found in slow- or moderately-flowing waterways, where they prefer to live among rocks and crevices, and the major southern tributaries to the Amazon in Brazil. The Rio Xingu, Rio Tapajos and Rio Tocantins, are characteristic examples of where they live. 

These rivers have high temperatures of 27-32°C, with mostly fast-flowing clearwater — there are only a couple of Hypancistrus known from blackwater habitats. The temperatures and the geology of these habitats results in a considerable diversity of fish species in these rivers. 

The depths at which you can find them varies greatly. For example, in the Rio Xingu you can find some Hypancistrus just a metre below the surface, yet in other parts of the river certain types such as L174 are only found deeper down at 20 metres or so. Despite their choice of rheophilic real estate, Hypancistrus are rarely found in the strongest current, usually preferring the quieter sections of their habitats.

Why so popular?

Some factors obviously contribute to the popularity of these fishes. First and foremost, their nice looks, with striking patterns of stripes or spots make them appealing. Another plus point for the everyday aquarist is their small stature, meaning they don’t need very big aquariums. Next, they are quite easy to keep if their basic demands are met and they will often breed under good conditions. The fact that they are readily available on the market, pretty well known and talked about in fish communities, also adds to their popularity. In short, Hypancistrus are suited for a wide range of fishkeepers. 

 Not all types of Hypancistrus are common in the hobby, and there are some factors which affect this. Some are regularly collected and exported from their native countries, while some are very rarely collected at all because of the remoteness of their habitats, and difficulty reaching them. 

Some are rare even in the wild, or have a very limited range of distribution, while others are even illegal to export from their native country, such as H. zebra. This results in unfortunate smuggling across borders of neighbouring countries (where export isn’t banned, despite the fish’s non-native status), from where they’re often shipped internationally — mainly to Asia. 

Read the rest of the feature in the June issue, available to read instantly on our digital edition HERE  or purchase the print edition HERE.

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