A number of natural effects and anthropogenic activities are known to significantly alter the integrity of freshwater bodies. This is a problem that has promoted the development of chemical or biological strategies to identify and quantify the damage in freshwater ecosystems; it is fundamental knowledge that should be followed by preventive or corrective measures. The use of biomonitor organisms belonging to plant and animal phyla for this has proved their usefulness, mainly because of the idea that any change in the ecosystem should be reflected in the selected organism. However, an appropriate biomonitor should possess several essential characteristics to properly carry out its function. Crayfish are a large group of aquatic macroinvertebrates that have shown sensitivity toward a variety of stressors. They are known to respond in various forms, including metabolic, histologic, and genotoxic changes. For the latter, studies have mainly applied the single cell gel electrophoresis (Comet) assay and the micronucleus test. In this context, Cambarellus montezumae is a particular crayfish that has most of the appropriate characteristics required for a biomonitor; it lives in a variety of freshwater bodies in México. Besides, it has been widely evaluated in many aspects of its biology and its nutritive value, as well as its growth and reproduction for aquaculture purposes. Moreover, the crayfish has shown dose- and time-dependent responses with respect to the effects of pesticides, suggesting then that it can be proposed as a non-conventional freshwater biomonitor.