it depends what u wanna do. if u weren't planning on keepeing them, just let them where they are n the other p's will eat them soon. if u want to keep them, u MUST remove them softly in another thank, with the same water they were born in. u'll loose maybe 1 third just by natural selection. once there will be too much difference in size between ur smallest n biggest babies, u must separate them again if u hope to keep them all.
for further details go search on the net, i red articles about people who raised hundreds of ps.