new to saltwater & reef aquariums

Hello all and thanks for the warm welcome I've already received. I'm an avid aquarist with 5 freshwater tanks and I've finally worked up my nerve to dive into saltwater (see what I did there? Today I set up my Fluval Evo 13.5 - see pic below. I used 13-14 lbs of Carib Sea Life Rock and 10 lbs...

I have a Reef tank running about 15 months. I found this on the underside of my filtration pad. It must have come up from the live rock. There were also about twenty copepods in there as well. I removed the big ones and placed them back into the tank. Is this safe to put back into the tank...