Field sites

San Marcos River, San Marcos, Texas
(Co 101)

In the San Marcos River in Central Texas we study the Amazaon molly and its sexual host species, the Sailfin molly (Poecilia latipinna). Both species were introduced in this river system.

County 101

San Marcos River, San Marcos, Texas (Martindale)

The fieldsite in Martindale is only few miles downstream from Co 101.


Lincoln Park, Brownsville, Texas

In South Texas, Amazon and Sailfin mollies are native and occur in all kinds of habitats, such as this oxbow lake in Brownsville.

Lincoln Park

Luis and Carolyn stand next to the OU Tahoe soaking wet after collecting some fish

Luis and Carolyn at Lincoln Park

Weslaco, Texas

Amazon and Sailfin mollies also colonized a variety of man made habitats, such as this drainage ditch near Weslaco.


Cueva del Azufre, Tapijulapa, Mexico

The Cueva del Azufre in the state of Tabasco in Mexico is the only known habitat of the Cave molly. The cave is not only dark, but contains also high concentrations of toxic hydrogen sulfide.


El Azufre, Tapijulapa, Mexico

The outflow of the cave - the El Azufre - also contains hydrogen sulfide and harbors a huge molly populations. Other fish species are essentially lacking in this system.

El Azufre

Arroyo Cristal, Tapijulapa, Mexico

The Arroyo Cristal is a creek in the vicinity of the Cueva del Azufre. It lacks sulfide, but harbors a diverse fish fauna.

Arroyo Cristal2

Rio Oxolotan, Tapijulapa, Mexico

Both, the El Azufre and the Arroyo Cristal, finally drain into the Rio Oxolotan, which is part of huge Rio Grijalva river system.

Rio Oxolotan