My co-worker gave me some small pieces of hydrophelia. I planted them in the tank, but they barely had any roots, so they stuck in the gravel for a while, but my goldfish would always take them out. They have been floating around and around my aquarium for quite some time now (better part of a month) and so there a little roots and some new parts growing. Any helpful hints on how to keep these things in the ground and stopping those goldfish from digging them out! Thanks in advance!