Granulomatous Gastritis in Juvenile Discus (Symphysodon sp.)
IAAAM 1999
Roy Yanong1; Eric Curtis1; Ruth Francis-Floyd2; RuthEllen Klinger2; Hans Roese2; Ilze Berzins3; Pam Dennis4
1Tropical Aquaculture Laboratory, Department of Fisheries and Aquatic Sciences, University of Florida, Ruskin, FL, USA; 2Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL, USA; 3The Florida Aquarium, Tampa, FL, USA; 4College of Veterinary Medicine, Small Animal Clinical Sciences, University of Florida, Gainesville, FL, USA


Granulomatous gastritis has been described in both Old World and New World cichlids with several possible etiologies including Cryptobia iubilans infestation and improper diet. However, an increasing number of reports suggest that protozoans are the primary etiologic agents. This report summarizes one case involving a discus breeding operation in which juvenile discus were affected most dramatically.

A cichlid breeder experienced morbidity and mortality in his discus population over the course of several weeks. All life stages were affected. More mature and larger fish experienced morbidity but minimal mortality. Breeder discus turned dark, had increased mucus production, and became laterally recumbent for one or more weeks before recovering. Fish two months or older also were affected with limited mortality. However, two-to four-week-old fish experienced high mortality, up to 70% or more.

Wet mounts and histological sections of affected juveniles revealed several gastrointestinal parasites. Minimal numbers of nematodes and flagellated protozoans, presumably Spironucleus sp. or Hexamita sp. were noted in the intestine. Great numbers of another species of flagellated protozoan were found in many of the stomachs examined as well as within the intestinal tract. The primary pathologic lesion seen was granulomatous gastritis, and in some sections of submucosa, protozoans were seen within vacuolated cells, presumably macrophages. These gastric flagellates closely resembled, in both appearance and associated pathology, Cryptobia iubilans, but electron microscopic verification is pending. Microbiologic culture of kidney and brain were negative. During the outbreak, several chemotherapeutants were attempted in both bath and oral treatments with limited success. At least two other cases of presumptive Cryptobiosis have been seen in discus from different breeding operations throughout the United States. Attempts to culture the organisms in vitro are ongoing, as are chemotherapeutic field trials.


1.  Dykova I, J Lom. 1985. Histopathological changes due to infections with Cryptobia iubilans Nohynkova 1984, in two cichlid fishes. Journal of Applied Ichthyology.

2.  Francis-Floyd R, H Roese, R Klinger, R Yanong, V Blazer, 1998. Diagnosis and clinical management of granulomatous gastritis in African cichlids. Proceedings of the International Association for Aquatic Animal Medicine. Pp. 130-131.

3.  Greenwell MG, MJ Kinsel, RD Murnane, SL Poynton. 1998, An epizootic of Cryptobia in East African and Central American cichlids at the Shedd Aquarium. Proceedings of the International Association for Aquatic Animal Medicine. Pp. 112-114.

4.  Noga EJ. 1986. Diet-associated systemic granuloma in African cichlids. Journal of the American Veterinary Medical Association 189: 1145-1147.

Speaker Information
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Roy P.E. Yanong, BA, VMD
Tropical Aquaculture Laboratory, Department of Fisheries and Aquatic Sciences
University of Florida
Ruskin, FL, USA

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