flea like creatures in my tank

[primas]

can anyon tell me what these little tiny tiny flea looking things .. maybe dark yellow in color .. are crawling over the walls of my tank...ive had my tank for 3 yrs now and have never seens these... is this detrimental to my tank?... i have a 50 gallon with only a blue tang and 2 clowns... FO tank ... please help.. i just noticed them this morning becuz they are so small.. but they are moving and alive

 

[bang guy]

Copepods of some sort. They are probably harmless or beneficial. There are parisitic Copepods but they don't normally hang out on the tank walls.