Armored catfishes (Siluriformes: Loricariidae) are bottom-dwelling, armored fishes native to Central and South America. The Loricariidae is the largest family of catfishes with over 80 described genera and 700 described species. New species of loricariids are described every year. This research has largely been supported by funds from the All Catfish Project, a project funded by the United States National Science Foundation. All loricariids are covered by bony plates and have sucker mouths.

Loricariids are 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 and are active at night. Armored catfishes have also diversified in their eating habits; there are species that eat algae, invertebrates, and detritus. Additionally, there is one genus, Panaque, that is known for eating wood!
Many species of loricariids can also breathe air! Most likely, this trait was developed to be able to live in low-oxygen environment. Genera, such as Hypostomus and Pterygoplichthys, are well known for their ability to breathe air. This trait can make them heartier and may be one of the reasons they are often found in the aquarium trade. Some Pterygoplichthys can live up to 30 hours out of the water!

Parental care is also common in armored catfish. Loricariids are well known cavity builders and nest guarders. Male loricariids are often territorial during the nesting season and will guard both eggs and fry.

Armored catfish are VERY popular in the aquarium trade. Their beautiful colors, interesting shapes, and gorgeous armored plates make them very attractive to fish enthusiasts. They are typically sold as “plecos”, “plecostomus”, or “algae eaters”. Many people purchase armored catfish to clean the algae on the glass of their aquarium. However, many species do not eat algae and unsuspecting consumers may end up disappointed! 

Aquarium owners may also be surprised when their tiny pleco grows to be too large for the aquarium. Unfortunately, this has led many pet owners to release their plecos into streams, rivers, lakes, reservoirs, and other bodies of water around their homes. In many cases, released armored catfish cause problems in their new environments. To find out more, visit our invasion and our resources pages.

Invasion Information

Although the introduction of loricariids is common, scientists and natural resource managers do not understand the full extent of the ecological effects of these introductions. That is why we need the help of fishermen and other people who love to visit rivers, streams, lakes and reservoirs throughout the world. If you have information regarding an introduction, please visit the contact page.

Armored catfishes have several life history traits that make them successful invaders. They are medium to large armored fishes with broad environmental tolerances. Additionally, many species of armored catfishes provide parental care through nest-building and egg-guarding and have the ability to breathe air! Scientists and natural resource managers are currently trying to understand what these fishes do to the ecosystems they invade and how plecos affect other fishes and aquatic organisms in the systems they invade. 

In addition to the ecological impacts, the socioeconomic consequences of armored catfish invasion can be severe. In Mexico, loricariid invasion has been linked to reduced water quality and the collapse of large freshwater fisheries. For example, the Infiernillo Reservoir tilapia fishery in southern Mexico supported 46,000 people through fishing and processing jobs. After loricariids entered the reservoir, the fishery experienced a 70-80% reduction in tilapia production. Subsequently, unemployment rose and led to the emigration of young men and women from affected communities (see Mendoza et al. for more information:

In their invaded habitats, loricariids obtain new common names. In Mexico, they are known as the devil fish (el pez diablo) and in the Philippines, loricariids are known as the janitor fish. 

We are trying to collect more information about the pleco invasion throughout the world! If you have documented plecos in a new invasion site (outside of Amazonian South America, Costa Rica or Panama), we would love to know about it!

Please send your information to  If possible, send your contact information, photos, a description of the site, and the GPS coordinates of the invasion site or click on the buttons above or below.