In a study on the effectiveness of Arosurf (a monomolecular surface film) MSF for the control of Coquillettidia perturbans, we surveyed microcrustacean populations to determine whether they were being impacted and whether species of potential use in mosquito control were present. Impacts on the microcrustacean populations were not detected. Among the copepods identified were Acanthocyclops vernalis, a mosquito predator and a host to at least 2 mosquito parasites, and 2 species of Macrocyclops, one of which, Macrocyclops albidus, is also a known mosquito predator.