New critters

Question
I noticed while doing my twice weekly water check that, there are about 25-30 little "critters" crawling around on an artificial plant in my 29 gal tank which is inhabited by two bubble amenomes, a Yellow Tang, 3-4 small Damsels, 3 Turbo Snails, and two Clown Fish. The tank has 15-20 lbs of live rock and has been quite balanced and healthy for the last 6-months. The new "critters" look like the one or two which were on the fully cured live rock which has been in the tank since start-up. Question is to whether these "critters" will harm the rest of the marine life and what, if anything, I need to do to keep everything healthy. Water chemistry is balanced except for a Nitrate level of 80 which I will correct with more frequent water changes. any suggestions?

Answer
Check out this link if this is what they are, let them be good source of food. Copepods.... here is the link

http://saltaquarium.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=saltaquarium&cd...