Yup, you guys apear to be right, copepods. Some of the images were bang on. I have been trying to encourage diversity in my one tank. I guess I should be careful about intoducing some of my critters into other tanks. These guys apparently can be harmful to fish. I have them in my shrimp/snail/molusk tank right now along with a few other small critters.Thanks for pointing me in the right direction on these.