The Common Pleco (Hypostomus plecostomus) is an armored catfish in the Loricariidae family. A distinctive characteristic of this family is the presence of longitudinal rows of armored scutes that cover the upper part of their body, providing the fish with effective protection against predators. The genus name Hypostomus comes from the Greek words hypo (“under”) and stoma (“mouth”), referring to the fish’s ability to cling to solid surfaces via its ventral mouth, earning it the common name suckermouth catfish.
The preparation of this exhibit was a lengthy and meticulous process, spanning nearly six months from April to October 2025. Every detail, from the patterns and coloration of the armored scales to the structure of the mouth and fins, was recreated with exceptional precision to ensure zoological accuracy. On October 20, 2025, the taxidermied specimen was officially added to the museum’s collection, becoming a valuable exhibit illustrating the themes of aquaristics and invasive species.
The Common Pleco is a benthic fish, primarily dwelling at the bottom of aquatic habitats. It is naturally found in tropical regions of South America, including Brazil, Guyana’s coastal Oyapocó and Essequibo river basins, and on the islands of Trinidad and Tobago. This species inhabits both freshwater and brackish environments, tolerating temperatures from 20°C to 28°C. During the breeding season, it digs deep riverbank burrows for spawning.
While the Common Pleco is rarely consumed as food, it holds a significant place in the aquarium trade. They are particularly valued for their efficient algae cleaning capabilities. Although primarily herbivorous, these species can also feed on small crustaceans.
These plecos can grow up to 50 cm in length, though their typical size is about 28 cm. Their lifespan can extend to 15 years. Body coloration ranges from light sandy tones to dark brown, often marked with a marbled pattern. They spawn among submerged roots, attaching their eggs to cleaned surfaces. Both the male and female guard the nest, aerating (oxygenating) the water until the larvae hatch.
A notable physiological adaptation is their ability to breathe atmospheric air, which is particularly important when oxygen concentrations in the water are significantly reduced. The swallowed air is absorbed in the stomach. This mechanism also increases the catfish’s buoyancy, facilitating feeding on vegetation.
In both popular and scientific literature, there are ongoing issues with the identification of this species, as several very similar species are often referred to by the same name—Hypostomus plecostomus. Furthermore, a number of armored catfish species have been introduced worldwide and are mistakenly identified as H. plecostomus. Hybridization between similar species (e.g., Pterygoplichthys pardalis and P. disjunctivus) complicates identification, and DNA analysis is often required for correct species determination.
In many countries around the world, the Common Pleco is considered an invasive species. Consequently, the farming, breeding, and trade of these fish are often prohibited.
Egidijus Bacevičius, a researcher at Klaipėda University, described a unique case in his article “Exotic Fish in Lithuanian Waters”: on August 20, 2018, a Common Pleco, about 16 cm long, was caught in a fish trap in the Curonian Lagoon, near Nida. It is presumed that this individual was released into the wild from an aquarium. Such irresponsible behavior can lead to serious ecological consequences, representing the first step toward the establishment of an invasive species.
If an unusual or unknown fish is observed or caught, it is crucial to transfer it to researchers for accurate species identification by specialists. Fish specimens can be delivered to the following institutions:
