SummaryWhite crappie, Pomoxis annularis, and black crappie, P. nigromaculatus, were hybridized to produce Fi and F2 generations. There was considerable tissue specific esterase gene function within each parental species. Many of the esterases were homologous but possessed different electrophoretic mobilities between the two species which permitted their use as gene markers. The pattern of inheritance and expression of a number of esterase genes was determined in the Fi and F2 interspecific hybrids.Although certain key morphological phenotypes characteristic of the black crappie predominate in the Fi hybrid, the enzyme phenotypes reflect the contributions of both co‐dominant parental genomes. There is a higher percentage of heterozygotes than expected in the F2 generation which may be indicative of heterosis. The genetic analysis also provided a better understanding of the polypeptide composition of these esterases.