In zebrafish,there are three clock genes named clock1a,clock1b and clock2.Here we reported zebrafish transgenic lines carrying a clock1a dominant negative fragment wherein per1a,per1b,per2 and per3 are all down-regulated under light/dark(LD)condition,though transcription of clock1a itself is not affected.The locomotor activities of these transgenic larvae are significantly higher than wild types under both LD and constant dark(DD)conditions.Furthermore,we also observed up-regulation of th,a gene encoding the rate-limiting enzyme in dopamine biosynthesis,potentially increasing the endogenous dopamine level of the transgenic larvae and resulting in their hyperactivity.We have generated clock1a mutants by TALEN,a clock1b mutant through ENU mutagenesis screen,and clock2 mutants by CRISPR/Cas9.These clock mutants should be helpful for elucidating their roles in circadian regulation.