various breeding experiments with the
species over the years.
Contrary to popular belief, the
Monterrey platy was once more
widespread than just Huasteca Canyon.
It inhabited springs, streams, ponds, and
rivers in heavily vegetated zones that
are now dry and part of the metropolis
of Monterrey, in Nuevo León. The type
location was probably a spring pool
at Cadereyta. Excessive pumping of
groundwater for the growing population
of Monterrey, as well as pollution, isolated
the species to a spring in Huasteca Canyon,
where it swam its last lap around 1964.
Dr. Myron Gordon, the famed geneticist
and Xiphophorus hunter, collected this
fish on several occasions from 1930
through the 1950s. The last population
in the hobby was collected in 1961 in
the canyon. The current population may
be a blend of these various collections
and is currently being maintained by
the Xiphophorus Genetic Stock Center
(XGSC) at Texas State University, in San
Still, continued problems maintaining
the species has resulted in the current
XGSC stock being descendants of 1992 and
1993 strains from outside sources, which
originally came from the 1961 collection.
XGSC staff claim the genetic diversity of
the hobby and scientific stock is extremely
narrow and, at most, homozygous. It is
fortunate that Xiphophorus, unlike other
Poeciliids, are famed for their ability to
line breed for generations.
Monterrey platies Xiphophorus couchianus, female above, male below.
In 1983, a population of platyfish was
discovered from waters in Apodaca,
the center of Monterrey. It was listed
as “critically endangerd” in 1996, with
only a few hundred members of the
population restricted to Ojo de Agua de
Apodaca. In a paper in 2006 reviewing the
Xiphophorus genus, Drs. Klaus Kallman
and Steven Kazianis claim that urban
sprawl has engulfed the area, and that
this population, too, has become lost
either from spring failure, pollution, and/
or hybridization with other swordtails
and platies (wild or hybrids). In recent
times there were probably other species of
Northern Xiphophorus in the Apodaca area
that were lost before being discovered.
Kallman and Kazianis also point
out that Xiphophorus couchianus from
Huasteca Canyon does not resemble the
A pair of Xiphophorus couchianus from the Apodaca population.
Apodaca form. The Apodaca population that the Apodaca population may be a
exhibits “deep-lying” large melanophore hybrid with X. meyeri and/or introduced
spotting. X. meyeri, which was also found hobby strains of platies and swordtails,
in the area and is closely related, exhibits whose unfortunate placement has been
similar large melanophore spotting on its reported. A collection from the Apodaca
flanks. Dr. Myron Gordon, who collected population is being maintained by the
X. couchianus from 1930 through the Universidad Autónoma de Nuevo León.
1950s, did not mention any specimens
with black blotches. Kallman also
studied these fish in 1960 and 1961 from
the Huasteca Canyon, and in its Rio St.
Catarina outflow, and also observed or
collected only unspotted specimens.
While the possibility of a spotted version
of X. couchianus “cannot be rejected”
according to the authors, one can speculate
Now that we have attempted to sort
out the history and natural status of
this beloved Monterrey platy, we can
move on to discuss the behavior of
this animal. Looks can be deceiving
here. True enjoyment of Xiphophorus