Medium. The Autumn Fern Plants are a colourful addition to any aquarium. Each plant is attached to a ceramic weight which makes positioning the plants in the aquarium very easy. These simple to arrange aquarium plants are supplied in packs of two with full instructions and planting tips on the reverse. The Autumn Fern Plants are a great way to redecorate your aquarium over the autumn period, matching your biOrb to the season and adding additional interest.