Plants inĀ container water gardens will need to be brought indoors for the winter. Potted plants can be lifted out of the water and stored in water filled tubs in a cool, dark basement. They will go dormant and can be brought back to the garden in the spring after the weather warms. Floaters may be overwintered indoors in aquariums where there is high light. It may be best to handle these as annuals and buy new plants each season. Any fish in container water gardens will have to be brought inside for the winter since the water may completely freeze and kill the fish.