Small, enclosed lake is in a tourist area called "Los Negritos", by the prominences a few steps from the lake on a perimeter of tens of meters with hot pools and mud bubbles. The lake originally belonged to Lake Chapala, so the group of fish present here derives from that. This is an endorheic vessel with at least one deep water inlet to the center, with a slight salinity (2.14 to 2.38 0/00), which is precisely greater at the point of upwelling and at a depth of approximately 36 m. This study to date has continued to collect and take data, also presents the characteristic of being an area of saline soils and halophilic vegetation. This body of water we consider is as relevant as that of Alchichica in Puebla. Its study is by monthly sampling with “chinchorro” and "chango" type trawl, recording morphological parameters, also environmental variables in the water, with a Data Sonde 4 brand Hydrolab. Knowing the structure and temporal dynamics of this fish community, along with the physical and chemical characterization of the water and implementa-tion of Importance Value Index (IVI).