Scientists have undertaken a study investigating the spatial distribution of cichlids in Mexico's Usumacinta River basin.
Miriam Soria-Barreto and Rocio Rodiles-Hernandez studied the cichlids of the Tzendales River, a tributary of the Usumacinta in the Montes Azules Biosphere Reserve in Central America.
They found 14 different species of cichlid, nine were native to the area and five were endemic - being found nowhere else other than this specific river basin.
Vieja intermedia and Amphilophus nourissati were the most abundant species and were found over the widest area, while the Firemouth cichlid, Thorichthys meeki and the guapote Parachromis friedrichsthalii were the rarest.
Several species were found in associations with other species.
Amphilophus nourissati, Petenia splendida, Vieja argentea, V. bifasciata, V. intermedia, V. pearsei, V. synspila and V. ufermanni occurred together, as did 'Cichlasoma' salvini and Parachromis friedrichsthalii and Thorichthys helleri and T. meeki.
Soria-Barreto and Rodiles-Hernandez also looked at the rheophilic species Theraps lentiginosus and T. irregularis.
These fish weren't found alongside the other cichlids, highlighting their specialisms for life in the faster-moving waters.
For more information see the paper: Soria-Barreto M and R Rodiles-Hernandez (2008) - Spatial distribution of cichlids in the Tzendales River, Biosphere Reserve Montes Azules, Chiapas, Mexico. Environmental Biology of Fishes, DOI: 10.1007/s10641-008-9368-0.