The objective of this study was to evaluate the effects of a supra-seasonal drought on the body condition of fish populations in the Santa Cruz Reservoir, located in the Brazilian semiarid region. A total of 5,820 specimens from different trophic guilds were analyzed. Biometric data, including standard length (cm) and weight (g), were used to calculate the length-weight relationship and the relative condition factor. Reservoir volume was categorized into three levels (high, medium, and low) to accurately evaluate the impact of water-level fluctuations on body condition. ANOVA and ANCOVA were applied to assess statistical differences in the length-weight relationship and condition factor with species at the three reservoir levels. Pearson's correlation was used to determine whether there was a relationship between drought and relative condition factor of fish. There was no statistical difference between the lines of the weight-length relationship for the species Hoplias malabaricus, Hypostomus pusarum, and Plagioscion squamosissimus. Leporinus piau showed a difference between the lines, according to each trained level, and Triportheus signatus showed a difference when the reservoir level dropped. The supra-seasonal drought influenced the alteration of body condition only of the species Hypostomus pusarum and Leporinus piau.