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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.

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Common name: Nyassa blue cichlid

Synonyms and Other Names: blue mbuna, Nyassa blue cichlid

Taxonomy: available through www.itis.gov

Identification: According to Eccles and Trewavas (1989), the genus Pseudotropheus is in particular need of revision and critical appraisal. Pseudotropheus zebra alone represents a complex of about 27 species (Ribbink et al. 1983). Some distinguishing characteristics of the species complex, a description of color patterns, figures, and photographs were given by Ribbink et al. (1983). Color photographs of various species and morphs were given in Ribbink et al. (1983), Axelrod et al. (1985), Lewis et al. (1986), and Axelrod (1993); also see illustrations in Petrovicky (1988). Size varies among members of the complex, with maximum size ranging from about 6 to 14 cm (Axelrod 1993).

Size: 6 to 14 cm

Native Range: Tropical Africa. Lake Malawi.

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: Probable aquarium release.

Status: Reported from Nevada.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: This species or species complex is well known in the aquarium trade. In its native range, the true P. zebra is distributed widely in Lake Malawi and shows marked geographical variation in coloration and markings (Ribbink et al. 1983). In contrast to references given in selected published fish lists (e.g., Deacon and Williams 1984), we found no mention of P. zebra in Courtenay and Deacon (1983), a review paper on introductions into Rogers Spring, Nevada.

There are no known voucher specimens; however, a photograph is on file to support record.

References: (click for full references)

Axelrod, H. R. 1993. The most complete colored lexicon of cichlids. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Axelrod, H. R., W. E. Burgess, N. Pronek, and J. G. Walls. 1985. Dr. Axelrod's atlas of freshwater aquarium fishes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Courtenay, W. - Florida Atlantic University, Boca Raton, FL.

Courtenay, W. R., Jr., and J. E. Deacon. 1982. Status of introduced fishes in certain spring systems in southern Nevada. Great Basin Naturalist 42(3):361-366.

Courtenay, W. R., Jr., and J. E. Deacon. 1983. Fish introductions in the American southwest: a case history of Rogers Spring, Nevada. Southwestern Naturalist 28:221-224.

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. Pages 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. Pages 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.

Deacon, J. E., and J. E. Williams. 1984. Annotated list of the fishes of Nevada. Proceedings of the Biological Society of Washington 97(1):103-118.

Eccles, D. H., and E. Trewavas. 1989. Malawian cichlid fishes: the classification of some haplochromine genera. Lake Fish Movies, Herten, Germany.

Lewis, D., P. Reinthal, and J. Trendall. 1986. A guide to the fishes of Lake Malawi National Park. World Wildlife Fund, Gland, Switzerland. 71 pp.

Petrovicky, I. 1988. Aquarium fish of the world. Hamlyn, London, England.

Ribbink, A. J., B. A. Marsh, A. C. Marsh, A. C. Ribbink, and B. J. Sharp. 1983. A preliminary survey of the cichlid fishes of rocky habitats in Lake Malawi. South African Journal of Zoology (Zoology Dierkunde) 18(3):149-310.

Other Resources:

Author: Nico, L.

Peer Review Date: 4/21/2006

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.