The authors attempted to evaluate the importance of interspecific competition and fluctuations in stream flow in determining the relative abundance and spatial distribution of rainbow (Etheostoma caeruleum) and fantail (E. flabellare) darters. The species exhibited considerable overlap in prey types utilized by each species increased in summer during periods of reduced resource availability. Fluctuations in prey availability had no effect on overlap in prey utilization. The distribution patterns of the species differed in substrate preference experiments but presence or absence of congeners did not influence substrate use. Microhabitat use appeared to be constrained by morphological characteristics of the species. These results suggest that in ecological time these species vary in their distribution and abundance independently of each other.