I started off with a few that came on some plants etc...then it seemed like they were just overtaking everything, breeding like crazy especially if you have lots of plants in your shrimp tanks.
What I found was that they would compete for the food the shrimps were getting too...ie: barley, algae wafers, even the BW grow....would push the shrimps out of the way for the food and even ate the algae/biofilm off the glass and filters.
In the end I noticed my baby shrimps not making it to juvie stages, and I have just emptied 2 tanks (nano 8 gallons) that were contaminated with these seed shrimps/cocopeds.
I took out all the shrimps and put in a pair of my Killifish...they have cleaned the tanks of every aquatic creature including planaria
My tanks are now clean enough to put shrimps back in and see if it makes any difference to the population growth.