insects

I came online to ask a question about some insects in a plant, and saw bluepony's post. I have a similar question, but the insects I saw were SO small they were almost specks, I couldn't see their legs or anything. they came on a hornwort that my boyfriend had, but he didn't have fertilizer or good light so virtualy all its leaves fell off and made an awful mess in his tanks. now its pretty much just sticks with a few leaf bunches on the ends here and there. I figured I might be able to "babysit" it until it perked up and then teach him how to care for it, but if it died I wouldn't be surprized. anyway, I had put it in a bucket at my house (not reuseing his water), fertilized it and put it in the light. then I noticed tiny specks swimming around the bucket and clinging to the sides and stuff. they may have been shrimp-like, I don't know, they were too tiny I couldn't see. I thought they might be contributeing to killing the plant. they were brownish-beige color, looked like moveing dots or lines, about a milimeter long.
can anyone identify them?
and how long should I quarentine the hornwort until I put it in my tank? I really don't want anything to happen to my other plants, they are all doing very well right now. thanks!

Guh!

okay, so I found out where they're really coming from. my gravel. I had syphoned some off into the bucket with the hornwort earlier, but didn't think much of it. today while doing a water change I looked at the old water after it settled, and sure enough, there are the bugs.
I don't know if they could be daphnia, I have never fed these fish live food yet. the closest they've gotten was freeze dried blood worms, which these are not. If it helps, when these insects move they kind of "hop" through the water, and then crawl along surfases they land on. they are too tiny for me to see in the actual aquarium, I think, I can only really see them in a white bucket in the light. they are also so small I've never seen my fish pay any attention to them