info on pods

[s10469]

How are copepods an different pods born? Larvae, eggs, or what. I found a bunch of little tiny black bugs crawling around in my tank, just in one area though. Hoping they are little baby pods, or at least something good that just hatched. I dont have much info though becouse they are so small. I did buy a tomato clown and a horse shoe crab the other day. Could they be a hitch hiker? What do you all think ?