Did any live? what you need is to make a rectangular net box, open at the top, with hooks to hang over the tank edge so that the top of the net is just out of the water. A wire coat hanger and two pairs of pliers would do the job. The mesh should be fine enough to keep the babies in but large enough to let microfauna through. A synthetic gauze would work -- you'd have to sew it by hand. Put some algae clumps in, or if you can get some fresh sargassum weed, shake a clump in a bowls of tank water and empty that in -- apparently the stuff has tons of tiny amphipods and ostracods. Alternatively, hang the baby trap in your sump if you have one; it will be rich in micros. Chuck in some brine ship eggs too. All just-hatched fish are omnivorous, even if they're going to be herbivores later.