This is a list of the fish I have found in Guatemala:
Species; Location
Amphilophus longimanus; Rio Nahualate & Rio Cojolate
Amphilophus macracanthus; Laguna Encantada
Amphilophus nourissati; Usumacinta River basin, Border with Mexico
Anableps dowei; Intercoastal channel in Escuintla, large schools
Archocentrus nigrofasciatus; Outlet of Laguna Encantada, Rio Siguacan
Archocentrus spilurus; Rio Motagua, Los Amates, Rio Sarstun
Astyanax aeneus; Rio Kilagua, Rio Motagua near Gualan in Zacapa
Carlhubbsia stuarti; Rio Dulce, Lake Izabal
Cichlasoma bocourti; Rio Sarstun, Rio Dulce, Rio Cienega
Cichlasoma salvini; Rio Sarstun, Lake Peten Itza, Rio La Pasion
Petenia splendida; Lago Peten Itza, Laguna Yaxha
Phallichthys amates; Rio Motagua, Rio Pajuila
Phallichthys fairweatheri; Rio la Pasion, Laguna Petexbatun and its tributaries.
Poecilia kykesis; Lake Peten Itza
Roeboides bouchellei; Rio Nahalate, various creeks in Escuintla
Theraps irregularis; Lago Izabal basin, Ri Polochic, Rio Dulce
Theraps lentiginosus; Rio Pasion, Rio Chixoy, Rio San Ramon
Thorichthys affinis; Lake Peten Itza, Laguna Salpeten, Laguna Yaxha
Thorichthys aureus; Rio Usumacinta, Rio Motagua, Lago de Izabal