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

It looks like the LEDs will draw about 500ma when all are on, but most of the time they blink so it's closer to 150 - 200.

I did put a resistor between the Arduino and the Optoisolator but didn't think about putting a transistor on the other side, to increase the amount of current the optoisolator can switch. I will look into that.

Thanks for the help,

Chris