Pecos assiminea (Assiminea pecos) is a species of endangered and highly understudied micromollusk. These diminutive snails occur in moist, karstic soil next to the slow flowing brackish water of the Pecos River in New Mexico and Texas, USA. Their population appears restricted to only three specific areas of known habitation within this range. Here, we studied survey methods, determined size range, variability in abundance over space and time, and how prescribed burns potentially impact their populations at Bitter Lake National Wildlife Refuge, NM. We tested five different survey methods and found that taking a soil core and microscopically examining it was the most reliable survey method. Pecos assiminea exhibits a preference for subterranean habitation and were found in their highest densities at a depth of 5 to 15 cm below the surface of the soil. We measured 1,729 shells and determined that average shell size is about 1.2 mm with some specimens measuring less than 0.5 mm. A temperature increase due to prescribed burns was measured at and 5 cm below the soil surface and lowered soil organic matter, bacterial, and fungal biomass in the soil. Soil electric conductivity and certain minerals increased after the fire. We were unable to demonstrate an impact of the fires on snail population due to high spatial variability and difficulty to distinguish between live individuals and empty shells filled with dirt. Future research will focus on finding additional populations via eDNA analysis.