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Texas Invasive Species Institute

Texas Invasive Species Institute

Armored Catfishes

Hypostomus plecostomus and Pterygoplichthys anisitsi

Class: Actinopterygii
Order: Osteichthyes
Family: Loricariidae

Hypostomus plecostomus and Pterygoplichthys anisitsi

Photographer: Pleco Source: www.wikicommons.org Copyright: Public Domain

Hypostomus plecostomus and Pterygoplichthys anisitsi

Photographer: U.S. Geological Survey Source: Bugwood.org ID: Pterygoplichthys sp. Copyright: CC BY-NC 3.0


The armored catfishes (Family: Loricariidae) are algivorous, mostly nocturnal, with a noticeable sucker located ventrally on the head. Loricariids can range in size from 3 inches to over three feet in adequate conditions. Their flattened ventral surface allows the fish to use their suckers on most substrates. The adipose fin has a spine and pectoral fins have thick, toothed spines that are used in male-male competition and locomotion.

Both Hypostomus plecostomus (Common Pleco) and Pterygoplichthys anisitsi (Paraná Sailfin Catfish) are Loricariids that are well established in Texas. They are often confused with one another because the black-lined patterns on these two fish species can vary significantly, and resemble one another.

Ecological Threat

With the over-abundance of Loricariids in freshwater ecosystems, local indigenous species can be out-competed and reduced. This could lead to a collapse of freshwater fisheries in addition to the obvious ecological dangers. While the Loricariids were introduced to control algae populations, it is unknown how effective these fish actually are at controlling them.


Loricariids are cavity builders and can lay more than 300 eggs in their nests. Males guard the nest and the eggs hatch within 4 to 20 days depending on the species. In addition to their successful breeding strategies, Loricariids are hearty fish that can withstand a wide range of ecological conditions. In fact due to their large vascular stomach, the fish can gulp air and survive out of water for more than 20 hours. Fishes in the genus Pterygoplichthys have been found to survive salinities up to 10ppt, allowing them to invade brackish habitats as well.


Loricariids otherwise known as plecos are naturally found in tropical South America, Panama, and Costa Rica. However, their range is increasing due to accidental and intentional human introductions throughout the world. Loricariids are frequently released into freshwater bodies in the United States and throughout the world by natural resource managers to remove algae and control aquatic plants. However, their effectiveness in controlling algal and plant growth in natural systems is undocumented.

Plecos are common in the aquarium trade, and tank dumps are a primary factor into their introduction intho the United States.

Perhaps the most ubiquitous species, Hypostomus plecostomus, was found in the headwaters of the San Antonio River in 1962, after individuals escaped the San Antonio Zoo. It and has maintained an obvious presence with a stable populations since 1990. Hypostomus plecostomus has also been found in Nevada, Hawaii, with isolated specimens found in Arizona, Colorado, Connecticut, Louisiana and Pennsylvania. Hypostomus plecostomus is the most geographically widespread of the Loricariids.

Pterygoplichthys anisitsi has been found in the Buffalo and Brays Bayous systems in Houston, TX since 2001. As of 2016, survey efforts have shown reproductive populations are being maintained. 

Native Origin

Central and South America.

Current Location

U.S. Habitat: Loricariids can be found in most freshwater habitats in tropical Costa Rica, Panama, and South America, but many species have small natural ranges. They can also be found in some brackish water habitats. Most loricariids are nocturnal. Armored catfish eat algae, invertebrates, and detritus however, there is one genus, Panaque, that is known for eating wood.


U.S. Present: Florida, Nevada, Texas, and possibly Wisconsin.

Texas: Reproducing populations of Hypostomus plecostomus occur in spring-influenced habitats of the San Antonio River (Bexar County), Comal Springs (Comal County), San Marcos River (Hays County), and San Felipe Creek (Val Verde County).

Reproductive populations of Pterygoplichthys anisitsi have been documented throughout Brays and Buffalo Bayous in Harris County; while Pterygoplichthys sp. is also established in the San Marcos River.




Management stems from controlling the fish trade. Advising owners to avoid releasing Loricariids into local waters is paramount in curbing the invasion. Breeding populations have been reported in Florida and Texas. Biologists working in Harris County started aggressive fishing strategies in Buffalo and Brays Bayous in 2016. 

**Never Dump Your Tank** By being a responsible pet owner you can prevent the spread of these pests in native freshwater systems.



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Barron, J. L. 1964. Reproduction and apparent over-winter survival of the sucker-mouth armoured catfish, Plecostomus sp., in the headwaters of the San Antonio River. The Texas Journal of Science 16:449.

Hoover, J. J., Murphy, C. E., & Killgore, J. 2014. Aquatic Nuisance Species Research Program. Ecological Impacts of Suckermouth Catfishes (Loricariidae) in North America: A Conceptual Model. Volume 14-1, March 2014. ARMY ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS AQUATIC NUISANCE SPECIES PROGRAM.

Nico, L. G., & Martin, R. T. 2001. The South American suckermouth armored catfish, Pterygoplichthys anisitsi (Pisces: Loricaridae), in Texas, with comments on foreign fish introductions in the American Southwest. The Southwestern Naturalist, 46(1), 98-104.
Norris, A. E. 2017. A Mesocosm Study of the Impact of Invasive Armored Catfish (Pterygoplichthys Sp.) on Endangered Texas Wild Rice (Zizania Texana) in the San Marcos River. University of Houston-Clear Lake.

Podkowa, Dagmara, and Lucyna Goniakowska-WitaliƄska. 2003. Morphology of the air-breathing stomach of the catfish Hypostomus plecostomus. Journal of Morphology. 257(2): 147–163.

Pound, K. L., W. H. Nowlin, D. G. Huffman, and T. H. Bonner. 2011. Trophic ecology of a nonnative population of suckermouth catfish (Hypostomus plecostomus) in a central Texas spring-fed stream. Environmental Biology of Fishes 90:277-285.

Power, Mary. 1990. Resource Enhancement by Indirect Effects of Grazers: Armored Catfish, Algae, and Sediment. Ecology. 71(3): 897-904.

Shafland, P. L. 1976. The Continuing Problem of Non-Native Fishes in Florida. Fisheries. 1(6): 25

Internet References:



Dan Foley, PhD. - Sul Ross State University - Rio Grande College - dfoley@sulross.edu
Krista Capps - plecoinvasion@gmail.com

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