The study was carried out to determine the effects of acute toxicity of clove powder to African catfish species commonly reared in Nigeria. Two fifty fingerlings each of C. gariepinus (mean weight 3.26 ± 2.30g and length 8.34 ± 1.82cm), and H. bidorsadis (mean weight 2.96 ± 1.80g and length 6.55 ± 2.84cm) were exposed to various concentrations (0, 50, 60, 70, 80, 100 and 120) for 96hours. The sequential behavioral responses (Opercular and tail beat frequencies) and cumulative mortality were recorded at the various intervals of 12, 24, 48, 76 and 96hours. Data obtained were subjected to a two way analysis of variance(ANOVA) and mean separation using Duncan multiple range test DMRT with statistical package for social science (SPSS). The responses of the OBF and TBF were similar in the both species, they were decreasing with increase in concentration and time. The mean values were slightly higher in C. gariepinus than H. bidorsalis. Mortality increased with increase in concentration and time for the both species. The 96hrLC50 for C. gariepinus (54.33mg/l) was slightly higher than that of H. bidorsalis (52.97mg/l). The MLT50 values of the decreased with increased in concentration and slightly higher in C. gariepinus than H. bidorsalis. The higher LC50 values of clove powder is an indication that it is less toxic to clariids, hence can be used to completely immobilized (anaesthetized) the fish in concentrations lower than 60mg/l without causing mortality.