The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Pterodoras granulosus
Pterodoras granulosus
(granulated catfish)

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Pterodoras granulosus (Valenciennes in Humboldt and Valenciennes, 1821)

Common name: granulated catfish

Synonyms and Other Names: Armado, bacu, common bacu

Taxonomy: available through www.itis.govITIS logo

Identification: Distinguishing characteristics of the genus Pterodoras were given by Higuchi (1992) and Sabaj and Ferraris (2003). A few distinguishing characteristics and a key to doradid genera were given by Burgess (1989), although that key should be considered somewhat suspect. The species was also included in illustrations and identification keys of Eigenmann (1925). For photographs of species see Goulding (1980), Sands (1984, incorrectly spelled as Pterydoras granulosus), and Burgess (1989).

Size: 70 cm TL

Native Range: South America, in the La Plata, Paraná, and Amazon basins and in coastal drainages of Guyana and Suriname (Sabaj and Ferraris 2003).

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Pterodoras granulosus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
FL197719771Tampa Bay

Table last updated 12/6/2021

† Populations may not be currently present.

Ecology: Primarily omnivorous, consuming a wide diet including filamentous algae, portions of terrestrial plants, benthic and terrestrial invertebrates, and other fishes (Hahn et al. 1992). It also feeds on palm fruits and may act to disperse seeds in the flooded forests (Goulding 1081). Pterodoras granulosus is a migratory species, making yearly spawning migrations during the rainy season (December - March) from large rivers and reservoirs into shallow flooded areas (Makrakis et al. 2007).

Means of Introduction: This fish was probably an aquarium release, as many species of Doradidae are popular in the aquarium trade.

Status: Failed in Florida.

Remarks: The Pinellas County, Florida, record is likely the basis for inclusion of this species in several published lists of unestablished, nonindigenous fishes (e.g., Courtenay and Hensley 1980; Courtenay et al. 1984, 1986; Courtenay and Stauffer 1990; Courtenay et al. 1991; Robins et al. 1991).

Voucher specimens: Florida (FDNR 11967).

References: (click for full references)

Burgess, W. E. 1989. An atlas of freshwater and marine catfishes: a preliminary survey of the Siluriformes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Courtenay, W. R., Jr., and D. A. Hensley. 1979. Survey of introduced non-native fishes. Phase I Report. Introduced exotic fishes in North America: status 1979. Report Submitted to National Fishery Research Laboratory, U.S. Fish and Wildlife Service, Gainesville, FL.

Courtenay, W. R., Jr., and D. A. Hensley. 1980. Special problems associated with monitoring exotic species. 281-307 in C. H. Hocutt, and J. R. Stauffer, Jr. Biological Monitoring of Fish. Lexington Books, Lexington, MA. D.C. Heath and Company.

Courtenay, W. R., Jr., and J. R. Stauffer, Jr.. 1990. The introduced fish problem and the aquarium fish industry. Journal of the World Aquaculture Society 21(3):145-159.

Courtenay, W. R., Jr., D. A. Hensley, J. N. Taylor, and J. A. McCann. 1984. Distribution of exotic fishes in the continental United States. 41-77 in W. R. Courtenay, Jr., and J. R. Stauffer, Jr., editors. Distribution, biology and management of exotic fishes. Johns Hopkins University Press, Baltimore, MD.

Courtenay, W. R., Jr., D. A. Hensley, J. N. Taylor, and J. A. McCann. 1986. Distribution of exotic fishes in North America. Pages 675-698 in C. H. Hocutt, and E. O. Wiley, editors. The zoogeography of North American freshwater fishes. John Wiley and Sons, New York, NY.

Courtenay, W. R., Jr., D. P. Jennings, and J. D. Williams. 1991. Appendix 2: exotic fishes. 97-107 in Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. Common and scientific names of fishes from the United States and Canada, 5th edition. American Fisheries Society Special Publication 20. American Fisheries Society, Bethesda, MD.

Eigenmann, C.H. 1925. A review of the Doradidae, a family of South American Nematognathi, or catfishes. Transactions of the American Philosophical Society 22:280-365.

Goulding, M. 1980. The fishes and the forest: explorations in Amazonian natural history. University of California Press, Los Angeles, CA.

Goulding, M., 1981. Man and fisheries on an Amazon frontier. Developments in Hydrobiology, v. 4. H.J. Dumont, ed. W. Tunk Publishers, The Hague.

Hahn, N.S., A. Monfredino Jr., R. Fugi, and A.A. Agostinho. 1992. Aspectos da alimentação do armado Pterodoras granulosus (Ostariophysi, Doradidae) em distintos ambientes do alto rio Paraná. Revista Unimar 14:163-176.

Higuchi, H. 1992. A phylogeny of South American thorny catfishes (Osteichthyes; Siluriformes; Doradidae). PhD dissertation, Harvard University, Cambridge, MA.

Makrakis, M.C., L.E. Miranda, S. Makrakis, D.R. Fernandez, J.O. Garcia, and J.H.P. Dias. 2007. Movement patterns of armado, Pterodoras granulosus, in the Paraná River basin. Ecology of Freshwater Fish 16:410-416.

Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. 1991. World fishes important to North Americans exclusive of species from the continental waters of the United States and Canada. American Fisheries Society Special Publication 21. American Fisheries Society, Bethesda, MD.

Sabaj, M.H. and C.J. Ferraris Jr., 2003. Doradidae (Thorny catfishes). 456-469 in R.E. Reis, S.O. Kullander and C.J. Ferraris, Jr., eds. Checklist of the freshwater fishes of South and Central America. Porto Alegre: EDIPUCRS, Brasil.

Sands, D. 1984. Catfishes of the world, volume 4: Loricariidae, Aspredinidae, and Doradidae. Dunure Enterprises, Ayr, Scotland.

Other Resources:
FishBase Summary

Author: Leo Nico, Matt Neilson, and Bill Loftus

Revision Date: 3/16/2020

Peer Review Date: 10/4/2012

Citation Information:
Leo Nico, Matt Neilson, and Bill Loftus, 2021, Pterodoras granulosus (Valenciennes in Humboldt and Valenciennes, 1821): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=666, Revision Date: 3/16/2020, Peer Review Date: 10/4/2012, Access Date: 12/6/2021

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2021]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [12/6/2021].

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