Give them lots of cover (plants), and remove the adults from them if you haven't already (they will eat the young readily). Feed them copepods, rotifers or moina, you can use golden pearls to feed the larvae. Do NOT use BBS. I couldn't access this stuff for my first batch, so I used smushed up egg yolk for food, worked just fine. It'll be easier to raise them after they morph into real shrimp, the larvae are a pain lol