I have those too, they also came off of a plant I had purchased, I found if you keep the light off at night than after about an hour turn it on and you can see all of them. Fortunately my gold barbs ate them all, I still have 1 or 2, but they are doing well because I have sand in the bottom of my tank and some algae so they clean up a lot. They also eat the dead plant leaves. Its hard to tell but they do some good if they are not overloaded.