Copepods are found in predator free zones, and are food for mandarins and wrasses. For seven years, I'd never seen one in my tanks, no matter how many hours I spent studying the sand and rock, day and night. However, one day I noticed tiny white specks on the glass of my son's tank, and there they were! Copepods are part of the food chain, and you can purchase them online and then add them to your refugium where they can breed in safety. More than reef-safe, these are reef-desirable. They eat small planktonic-sized foods, and are part of the food chain that consumes detritus. Dosing live phytoplankton to your tank will feed these little bugs, which increases their population for your fish to later feast upon. Reef-safe
They are really small, as you can see in this next image. That penny was placed in front of the glass to give you a sense of scale.
Here are the best I could muster with my macro lens.