The efficacy of using an anaesthetic, clove oil, to collect subtropical intertidal fish assemblage was compared with an ichthyocide, rotenone. The effect of different water salinities and temperatures while using clove oil was also compared. The fish used in the latter experiment was the large-scale mullet (Liza macrolepis), which is abundant in intertidal zones of Taiwan. Results show that the effect of salinity on induction time of fish differs significantly from high salinities to low salinities. Significant linear relationship was found between water temperature and the induction time. The individual and fish species numbers collected using clove oil (36 species of 13 families) and rotenone (39 species of 17 families) is slightly different in northern Taiwan from January 2000 to October 2001. These findings suggest that clove oil is a chemical as efficient as rotenone and therefore can be used to replace the latter in collecting subtropical intertidal fishes.