Gymnogeophagus is a genus of fish endemic to sub-tropical South America. Currently containing 10 described species and >8 undescribed species, this genus is distributed throughout Uruguay, Southern Brazil, Northern Argentina, Bolivia and Paraguay.
Established as a genus by Miranda Ribeiro in 1918, little activity occurred in this genus until 1975 when Dr. J.P. Gosse performed a revision of the Geophagus genus. He placed 6 Geophagus species in Gymnogeophagus that did not fit in the Geophagus, these included Gg. australe, Gg. balzanii, Gg. gymnogenys, Gg. labiatus, and Gg. rhabdotus. In 1988, Roberto E. Reis and Luiz R. Malabarba made a revision of genus, which included the description of Gg. meridionalis, and Gg. lacustris. Reis, Malabarba and Carla S. Pavalleni described Gg. setequedas in 1992. In 2000, Gg. che was added to the genus with a description by Jorge Casciotta, Sergio Gomez, and Nelly Toressani. Wolfgang Staeck made a description in 2006 that described Gg. caaguazuensis, making it the most recent addition to the Gymnogeophagus genus.
There are several recognized species within the hobby, and infrequently imported that are not yet described.
Reis and Malabarba created a key for identification for the Gymnogeophagus genus in 1988, modifying it (with Pavalleni) in 1992 to include Gg. setequedas. Click here to view this key.
Members of this genus, being from sub-tropical climates, require a wintering period for 3 months of the year. Particularly necessary for breeding, this wintering period should begin with a gradual decline in temperature until the temperature reachs the low 60s, where it should be maintained for apporxiamately 90 days. As the temperature begins to rise once again, the fish should begin their breeding activities, provided sufficient amounts of food are available and the water is kept clean.
