Inhibition of caudal fin regeneration in Corydoras aeneus by lithium chloride

► Caudal fin regeneration was inhibited or delayed after lithium treatment. ► The most affected structures in caudal fin are skeletal elements (lepidotrichia). ► Lithium exposure induces apoptosis of epidermal and blastemal cells. ► Some blastema cells exhibited a micronucleus-like structure after lithium treatment.