From Sanskrit अनिमिष (animiṣa, “almighty, unblinking, vigilant”), the name of a Deva, also said of a fish, अ- (a, “not”) + निमिष (nimiṣa, “twinkling, closing of the eye, moment”), in turn from निमिषति (nimiṣati, “shut one's eyes, wink, fall asleep”).
Animesh