Wallaby

Is it really necessary to have a sponge filter once they they get bigger? Or could I just cover the intake of a ten gallon filter with pantyhose and tie it on with a rubber band so they don't get sucked in? They're about the size of a pin head at the moment...

Also what are some good foods to be feeding them? Right now they're getting a little hard-boiled egg yolk squeezed through a cloth and Hikari first bites 3 times a day... Is that too many feedings? The egg yolk seems a little messy but it's really tiny and I'm worried the first bites might not be small enough since some of the fry are maybe period sized, at maximum...

Thanks!