surface bugs??

[colourfuldog]

I have set up a 20 gallon propagation tank about a month ago...
(PICS SOON) I have noticed some tiny insect body floating near my skimmer outlet..I didn't think anything of it I thought maybe some insects flew in and died.. I was cleaning the surface water when I had noticed the little bus where everywhere and seemed tobe attracted to the spotlight I had lit after my lights day/actinics where turned off..
Any one out there have/had these bugs??
They seem to float and skim on the surface really fast.
Are they ok for my tank?