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The <i>cyp19a1</i> gene codes aromatase that converts androgen to estrogen, which plays a central role in early female differentiation and ovarian development in teleosts. For the blotched snakehead (<i>Channa maculata</i>), an important aquaculture fish that is susceptible to hormone-induced sex reversal, two aromatase genes were characterized in the present study, <i>cyp19a1a</i> and <i>cyp19a1b</i>. We analyzed gene expression and the epigenetic state of <i>cyp19a1a</i> and <i>cyp19a1b</i> in different adult tissues: the gonad and brain from normal XX females (XX-F), normal XY males (XY-M), sex-reversal females (XY-F) induced by estrogen, and YY super-males (YY-M), and gonads at different development stages. <i>Cyp19a1a</i> exhibited strong female-biased expression patterns in the ovary, and <i>cyp19a1b</i> dominantly expressed in the brain with no sex bias. <i>Cyp19a1a</i>’s expression pattern in the XY-F ovary was similar to that in the XX-F ovary, with a relatively high expression level, which was far higher than that in XY-M and YY-M testis. Meanwhile, CpG methylation levels of <i>cyp19a1a</i> promoter were lower in XX-F and XY-F ovaries compared with XY-M and YY-M testis. A significantly negative correlation between the CpG methylation levels and <i>cyp19a1a</i> expression was elucidated in XX-F, XY-M, XY-F, and YY-M gonads. Furthermore, the strong female-biased <i>cyp19a1a</i> expression was closely related to ovarian differentiation and maturation, and the overall methylation levels of <i>cyp19a1a</i> promoter were inversely correlated with <i>cyp19a1a</i> expression. There were no detectable sexually dimorphic differences in <i>cyp19a1b</i> expression and CpG methylation levels of <i>cyp19a1b</i> promoter in the brain and gonad between sexes in <i>C. maculata</i>, thus the function of <i>cyp19a1b</i> in <i>C. maculata</i> needs further research. Our research illustrates that cyp19a1a is closely related to estrogen production, ovary differentiation/maintenance, and sex reversal, and epigenetic modification plays a crucial part in maintaining the sexual dimorphic expression of <i>cyp19a1a</i>, ovarian differentiation and oogenesis in <i>C. maculata</i>.