Tiny little bugs (I guess)

Question
I did a small partial water change the other night and as I was checking the water for newborn frys before throwing it out, I noticed some minuscule little bugs swimming!!!  I freaked.  Are they harmful?  Will they harm my fish?  I have a 1 year old 29-gal freshwater aquarium setup with: (23) Plattys (raised from birth), (1) Pleco, (1) Dwarf Frog, (1) Ghost Shrimp, (2) Algae Eaters.  I've never seen these bugs before.  You can even see them in the water.  I noticed them when I transferred the "to be tossed out" water to a plastic bowl to search for frys when i noticed them.  Could they of come from live bloodworms?  I feed these to my fish and frog.
Help!!!!!!
Thank you, Lynzie  

Answer
Hello,

I am not sure where these bugs came from, and with so little description its hard to say if they will or wont harm your fish. The best thing you can do is treat your tank for parasites as a precautionary measure. Check your local fish store for an anti-parasite and treat your tank.

Hope this helps! If you have any more troubles or concerns, feel free to contact me again!

Good-luck,
From Stephanie