Biotope description: Two years ago I discovered a population of endemic fish of recent scientific description: Profundulus mixtlanensis, in a stream of the municipality of “Santa María Peñoles” in the southern state of Oaxaca, Mexico (1884 meters above sea level). The stream is called “El Rosario” and born between a ravine where the pine-oak predominates, so a lot of leaves of these trees is clear, which nourish the soil and sink to the bottom of the pools that form the stream; the riverbed is composed of metamorphic rock, having large rocks to small, gray especially with the coated sand bottom slightly yellow color, taking over abundant decaying organic matter and soil that emerges from the edges, besides being submerged branches of dry brush or pieces of trees, there are roots of the vegetation that exists in the margin of the pools is introduced into the water, creating shelter for fish spawning substrates and “nursery” of the fry. At the bottom of the ponds, born some grass seed specimens falling margins. Adults and dominant fish tend to grab the leaves, where they hide beneath them and seek their food, youth are in the middle and at the top and near the vegetation that comes in contact with water or roots are hatchlings. Of the species that cohabit with “Profundulus mixtlanensis” is a species of frog genus Lithobates, and its tadpoles properly those found in the stream. On the banks of the stream, grow on some rocks moss genus Fontinalis and lichen on pieces of wood, as to the strict aquatic plants are not observed submerged, but in emerged state: Eleocharis parvula, Eleocharis acicularis, Bacopa monnieri, Fontinalis antipyretica, Nasturtium officinale (plant That was Introduced by the Spaniards in Mexico), grass, ferns and lichens not yet identified. The values of the physiochemical parameters of the stream are: pH: 7.2; GH: 220 mg / l; KH: 150 mg / l; NO2: 0.5 mg / l; NO3: 2.5 mg / l; NH3 / NH4: 0.1 mg / l; Cl: 0.8 mg / l; Ca: 80 mg / l; PO 4: <0.25 mg / l; Fe: 0 mg / l; O2: 4.12 mg / l (The observations are personal and are the first record).
Habitat Profundulus mixtlanensis, a pool of the stream El Rosario, Oaxaca
Eleocharis parvula, Eleocharis acicularis, Bacopa monnieri, Fontinalis antipyretica, Nasturtium officinale (plant that was introduced by the Spaniards in Mexico), grass, ferns and lichens not yet identified