Coacuilco, a wonder of the Huasteca

_th place in Biotope Aquarium Design Contest 2020

Volume: 270 litres
Dimensions: 90x60x50 cm
List of fishes: Xiphophorus birchmanni
List of plants: Theres no plants
Description of decorations: The biotope its compose by silical sand and river rocks or roundish rocks, so i use the same substrate and rocks that you can find in the habitat, in the river theres an absence of any type of aquatic plants.
Description of equipment: Planet aquarium tank, custom made led light, the filter its a fluval 304
Water parameters: 24°C, 7.6 ph.
Additional info: I make water changes every single week by 50%, and clean the glass of the algae that starts to form


Description of the area surrounding the biotope: Coacuilco its an small town in the state of Hidalgo in México, next to the village theres a river with medium to fast flowing stream depending on the season, the river its often visited by tourist and swimmers. Theres a lack of vegetation in the water, in some months mainly on the dry season you can see some algae attach to the rocks, because of the poor circulation and acumulation of debris. The bottom of the river its conformed by silical sand and rounded rocks and pebbles very calcaric. The river its sorrounded by some terrestrial vegetation such as tress like Ulmus sp, Adiantum tenerum, Sphagneticola tribulata, among others.
Description of the underwater landscape of the biotope: As i mention, that its a fast flowing river so the rocks are round because of the erotion, and the fishes use them as a protection of predators, the sand its siphoned by the fish in search for food, but they also graze the rocks, trying to eat some auwfuchs.
Description of the parameters of the habitat: The temperature of the habitat varies, between 14 C to 35 C, depending of the season, the water its always cool, and stays between 20 to 22 C
List of fishes and invertebrates occurring in the nature biotope: Xiphophorus birchmanni, Herichthys pantostictus, Notropis tropicus, Poecilia mexicana, Gambusia regani, Astyanax mexicanus
List of plants found in the nature biotope: none
Threats to the ecology: One of the main threats for the river its, the problem that the town Coacuilco have with the sewer system, cause its inefficient, and some of the water ends in the river system, causing pollution, the goverment its working to implement a treatment plant for water and waste. But theres also another threat, the river its sorround it, in some parts, with agricultural fields, where the farmers use pesticides that also ends in the water, washed by the rain, so its almost imposible to spot the leak, but why? because in the past that part of the country suffer from felling of trees, so as we can see theres a lack of environmental services.
Sources of information: – Los Peces Dulceacuicolas Mexicanos. Listados Faunísticos III, UNAM, Instituto de Biología, Héctor Espinosa Pérez, Ma. Teresa Gaspar Dillanes, Patricia Fuentes, 1993.
– Revision des Xiphophorus montezumae/cortezi – Komplexes und Nebeschreibung einer subspezies, Lechner and Radda 1987.
– Freshwater Fishes of México, Robert Rush Miller, The University of Chicago Press, 2005.

Comments of the members of the jury of Biotope Aquarium Design Contest 2020