El Azufre spring, Tacotalpa, Grijalva, a high hydrogen sufide (H2S) content spring near the village of Tapijulapa, Tabasco, México where a few individuals of Cichlasoma salvini were recorded. The El Azufre is directly connected to the Cueva del Azufre, where a cave morph of Poecilia mexicana can be found.攝影者 Michi Tobler.