There's no need to feed them. Just make sure that you're there as soon as the shipment gets to your door... don't let it sit in the sun. Open the package carefully. There's also no need to "rinse" the rock out... just dump it in, let the dust settle, and then get busy on aquascaping. Just make sure that the rocks are sturdy and don't move around... don't want a rock to fall against your glass and crack the tank 8O