Here is some additional information that I have received from Juan Miguel regarding this species.
Paratheraps fenestratus (See generic discussion in the forum) is not endemic
to Rio Coatzacoalcos, in fact it can not be found in Rio Coatzacoalcos, its
distribution ranges from Rio la Antigua in the north to Rio Papaloapan in
the south, where it has its largest population. Normally it is found no
higher than 500 m OSL but in the spring it can go up to 1,000 meters OSL. In
recent years exotic populations have been observed as north as Rio Cazones.
It is a gregarious fish which feeds mostly on vegetable matter.
All the best
Juan Miguel Artigas Azas
The Cichlid Room Companionhttp://www.cichlidae.info