Can an optoisolator do this or do I need a relay?

Hi thanks for the example but for this application I didn't need a high powered relay -- I have a 5v one that works directly off a digital pin.

I was looking to see if using an optoisolator + transistor instead a relay reduced power consumption enough to make running the system of AA batteries viable, but I think the draw from 96 LEDs means I'm stuck with a wall wart or D cells.

Thanks,

Chris