I recently bought three bunches of aquarium plant cuttings, but am having difficulty getting them to grow. 1 of the bunches has been completely destroyed by the goldfish, and the other two are going the same way. The problem is that I cannot get the cuttings to stay in a stable position within the gravel (they either get pulled out or just rise up). The cuttings still have the sponge and metal weight around them as this is the only way I can get them to sink, I've tried jamming them under things, but they do not grow. Should I take them out to make maintenance easier? What do you think?