rhabdotus. It can be entertaining to watch
the behavior of this cichlid in the wild.
In clear-water streams, the females can be
seen taking care of the tiny fry, while the
male patrols and dominates many breeding
females within his territory.
Gymnogeophagus labiatus “El Tigre.”
it meets with the Río Uruguay. This
expansive river system is home to another
undescribed species of Gymnogeophagus,
which are distinctly different in shape and
coloration from G. gymnogenys. Although
a little muted in color, the males display
an impressive nuchal hump—the largest
of any of the Gymnogeophagus discussed
here. This species seems to inhabit only
sandy bottoms of large rivers. In breeding
mode, the males may be a pale yellow
to a light olivaceous color. Nice red fins,
the caudals in particular adorned with
large, perfectly circular dots, complete
their appearance nicely.
This is an undescribed species of
Gymnogeophagus that has been collected
in six different locations along the Río
Negro. They can be found alongside G.
gymnogenys and G. meridionalis.
They appear to be rather peaceful and
well behaved in aquariums. Very little
information on their behavioral ecology is
known at this time.
Gymnogeophagus labiatus “Centurion.”
The most ancestral of the mouthbrooding
gymnos is G. labiatus. They are found in all
of the Merín Basin. This is a wonderful-looking fish with orange and bright blue
colors, shimmering striped dorsal and
caudal fins, and very thick lips. G. labiatus
has been slowly and deservingly attaining
popularity with cichlid enthusiasts.
Once again, phenotypic variation in
coloration, body shape, and the patterning
of the fins from the different localities
can be observed. Some possess elongated
spots in the dorsal fin instead of straight
lines (predominant in most populations),
and from other localities, the same thing
is seen with the caudal fin design. The
most beautiful of this magnificent fish
species must be the G. labiatus that
comes from the far northeastern side of
the country, in Centurion. In this race,
the cheeks and flanks are strawberry red
with iridescent steel-blue lines and spots
running throughout the body and fins.
Catching a fully grown male with brilliant
colors and a giant nuchal hump is a sight
not soon forgotten!
In captivity it is, like most mouthbrooding
gymnos, a peaceful and plant-tolerant fish.
They are not choosy about foods and prefer
to spawn at a temperature of 73° to 77°F.
In nature, we have collected them
on rocky or sandy bottoms in flowing
waters. Oftentimes they can be observed
cohabitating with G. gymnogenys and G.
SP. AFF. LABIATUS
In the northern corners of Uruguay, some
species with intermediate characteristics
between G. gymnogenys and G. labiatus
exist. These species are all thick-lipped,
just like G. labiatus, but they have a dotted
design pattern in both the dorsal and
caudal fins, which can also be found in
G. gymnogenys. Despite having similar fin
patterns, their coloration and humps differ
significantly from G. gymnogenys.
There is much mystery surrounding
these unclassified fish, as very little
behavioral information exists, and more is
needed to determine if these are actually
one or several new thick-lipped species.
Rocky bottoms and clear streams are
preferred in nature. Breeding occurs in the
summer, when females holding eggs are
Give Them a Try
Of the species represented here, only
G. sp. aff. meridionalis, G. balzanii, and G.
labiatus are seen with any frequency in the
aquarium trade. Words do not do justice
to the beauty of these cichlids when well
cared for. Their best qualities, besides their
obvious good looks, are small size (all
under 8 inches), rather mild temperaments,
and—for those hobbyists who find their
utility bills too high—a preference for
Malabarba, L. R., R. E. Reis, R. P. Vari, Z.
M. S. Lucena, and C. A. S. Lucena. 1998.
Phylogeny and Classification of Neotropical
Fishes. Porto Alegre, Edipucrs.
Malabarba, L. R and R. E. Reis. 1988. “Revision
of the Neotrópical Genus Gymnogeophagus
RIBEIRO, 1918, with Descriptions of Two
New Species (Pisces, Perciformes).” Revista
Brasileira de Zoología. pp. 259–305.
Wimberger, P. H., R. E. Reis, and K. R.
Thornton. 1998. “Mitochondrial
phylogenetics, biogeography, and evolution
of parental care and mating system in
Gymnogeophagus (Perciformes: Cichlidae).”
Phylogeny and Classification of Neotropical
Fishes. Porto Alegre, Edipucrs. D