Taxonomy
Order: Siluriformes
Suborder: Loricarioidei
Family: Loricariidae
Subfamily: Hypostominae
Genus: Parancistrus
Species: Parancistrus nudiventris, Rapp Py-Daniel & Zuanon, 2005
Description
The Parancistrus nudiventris L31 is a described catfish species in the Loricariidae family that is only found in the Rio Xingu, near the city of Altamira in Brazil. In the aquarium hobby it is also known as Peppermint pleco. To clarify: the common name Peppermint pleco is broadly applied in the hobby to several dark, spotted Loricariidae, including the most well-known variant Ancistrus dolichopterus L181.
The main characteristic of the P. nudiventris is its short, flat, and broad body, which makes it very robust. It has a dark base color covered with small, bluish-white spots. The species grows to approximately 20 cm in length; the species description lists it at 17,5 cm.
It also has extremely large gill openings, typical of the Parancistrus genus. Furthermore, this species has a membranous connection between its dorsal and adipose fins.
Given its large mouth and large gills indicate that this species requires a lot of oxygen. The oral teeth are filamentous/bristle-shaped, well-developed but infrequent, and slightly knobbed. This makes it an effective grazer, foraging algae and small invertebrates from rocks.
The name nudiventris comes from Latin, and nudus means naked, bare, uncovered. Ventris means belly.
Distinguishing features of the L31:
The P. nudiventris differs from its close relative, the Parancistrus aurantiacus, in several morphological and colour characteristics:
- • Color pattern: The P. nudiventris has small, bluish-white spots. In contrast, the P. aurantiacus is uniformly dark, mottled, or marbled, but never speckled.
- • The belly (naked abdomen): The most distinguishing feature, according to the official description of this species, is the completely naked ventral surface from the mouth to the anus. In P. aurantiacus, this part is completely covered with plates.
- • Head and body shape: This pleco has a short, broad, and flat body. Compared to P. aurantiacus, the L31 is slimmer and has a narrower interorbital distance.
- • Mouth teeth: The L31 has more prominent and well-developed oral teeth than its relative. This characterizes it as an Aufwuchs-grazer (omnivore). It feeds on algae and other periphyton food scraps, but also eats animal remains (insect larvae and microcrustaceans).
Distribution and habitat
The Parancistrus nudiventris is an endemic species found only in the Rio Xingu basin in the Brazilian state of Pará. This river is one of the largest and most ecologically unique tributaries of the Amazon.
The Xingu Riverbed consists 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 (84 °F) to over 33 °C (91 °F) in the shallower sections. The water is soft and slightly acidic.
According to research, the fish lives primarily individually or in pairs at depths of up to about 2 meters. It is nocturnal, sheltering during the day under large boulders or in narrow crevices of submerged rocks.
The L31 is found in rapids and areas with moderate to strong currents, 40 to 190 cm/sec. Juveniles (up to 5 cm) are also observed under flat rocks on the bottom. It is a rheophilic species (loving currents).
Parancistrus nudiventris shares its habitat with a wide variety of other Loricariidae, including species such as Baryancistrus spp., Oligancistrus punctatissimus L30, Ancistrus ranunculus L34, Peckoltia vittata L15, and Hopliancistrus tricornis.
Diet
Parancistrus nudiventris is an omnivore that feeds by grazing on rocky surfaces. This feeding strategy is also called "kammer" (comber).
The species has a very long digestive tract (about 20 times the standard length), which is typical of algae-eating fish.
Analysis of the stomach contents of two preserved wild specimens shows that the diet consists primarily of:
- Algae (Diatoms): This is the most frequently ingested food.
- Other food remains: Blue-green algae (Cyanobacteria), plant debris, bryozoans, chironomid larvae, microcrustaceans, and some small mollusks.
- Non-food components: A significant amount of sand and silt, which is likely ingested unintentionally during grazing on the rocks and may be essential for digestion.
What do I feed my Parancistrus nudiventris L31?
In the aquarium, especially in the beginning, it is important to offer them several meals a day with a varied diet consisting mainly of vegetable material.
I mainly feed my P. nudiventris EBO Spirulina paste (which I spread on a stone so they can graze naturally), EBO Spirulina soft granulate, EBO Veggie sticks and sometimes I alternate this with Futterdose Krill soft granulate.
Aquarium
Minimum size 100 - 120 cm.
Keeping this species in a home aquarium requires specific conditions, particularly regarding water quality, current flow, and water temperature. Therefore, it's not a pleco for beginners.
Since the fish normally lives between crevices in the rocks, there must be sufficient breeding caves and/or hiding places in the aquarium. The aquarium can be set up with a sand bottom, smooth stones or boulders to imitate the natural rock bottom of the Rio Xingu. Alternatively, breeding caves or the special Rio Xingu crevice can be used to provide additional hiding places between the rocks.
They can be kept in groups, but keep in mind that adult males can be territorial toward each other and other Loricariidae. They defend their hiding places with their stongly developed odontodes.
These plecos are nocturnal and hide during the day, indicating they don't like bright light. On the other hand, light can promote the growth of algae and biofilm on the aquarium rocks, which the fish will graze on.
A very good filter is also crucial, as these fish naturally thrive in warm, fast-flowing, and oxygen-rich water and therefore need clean water at all times to stay healthy. Furthermore, they have a fast metabolism, which means the water becomes contaminated more quickly. Therefore, weekly large water changes are crucial.
Good surface flow/water movement and aeration are also essential, as this species, evident from its extremely large gill openings, requires a lot of oxygen.
Sex difference
Unfortunately, I don't currently have any photos of the sexing of the Parancistrus nudiventris. If anyone has an adult L31 that I could take photos of, please feel free to send me a message!
The sex difference is similar to Parancistrus aurantiacus.
Reproduction and breeding
Captive breeding has occurred only a few times so far. They lay their eggs in breeding caves, after which the male normally cares for the eggs and youngsters.
For this species I use round breeding caves measuring 6-7 x 24 cm and 8-9 x 28 cm. I also have Rio Xingu crevice medium in the aquarium.
Literature
Rapp Py-Daniel, L. H., & Zuanon, J. (2005)
Description of a new species of Parancistrus (Siluriformes: Loricariidae) from the rio Xingu, Brazil.
Neotropical Ichthyology, 3 (4): 571 - 577
