Since the plant must drain, the closure of the drainage hole(s) by its roots must be seen as trouble. It does appear the plant is crying out for a re-potting and since it is causing problems, the need to wait until spring sunshine is not what it should be waiting for; re-pot now. Make sure the soil drains well...but does retain some moisture. For that, possible use of a heavier than usual percentage of peat moss might be considered. It holds on to moisture longer and mixed with any of the good mediums....vermiculite, coarse sand, perlite and potting soil/mix the plant might do better. Repotting of course is going to show what extent the roots are in. If you are considering a total re-soiling, then I suggest you remove all the old soil, wash the roots clean and inspect for any sign of damage there. A barrier between the drainage holes and the soil will prevent somewhat the reoccurrence of the roots making it to the drainage holes. Stones of size, or shards of clay might be used. I like the broken clay shards because they leave important spaces so that water can drain well, yet block the path of soil that can plug up the hole. Go up one size only...repotting to a pot too large for the roots---even tho they have expanded--can cause future problems. Its alright to remove what roots are superfluous. Ferns, generally all, like their water and they can sometimes drop a measure of debris that makes the plant or the floor its sitting on, unsightly. But, in winter, even ferns don't grow all that much and need less water. A constant vigil by testing the soil dampness is one way to avoid underwatering/overwatering. Ferns too appreciate light....just not direct light. Give your plant more than usual at this time but give it a filter when the time comes the light intensity resumes. Mid February is the time we usually allow that plants begin to start growing. Its the time that geraniums and their ilk, come out of their cool storage to resume their voyage to summr sun. Until April tho, the sun takes its time to come up to light that influences greatly plants in windows and on window sills. Common sense should prevail. When it does begin to put on new growth in earnest, the time to begin feeding can resume. Fertilize every 3rd or 4th watering.

Yes, it appears to be a fern. Perhaps some type of Pteris.

OK thanks to Carol23 my pretty little plant is Selaginella uncinata! Selaginella uncinata, or Peacock Spikemoss*, is a very attractive form of Selaginella native to China. It is semi-evergreen in nature and has straw colored rambling stems with dimorphic metallic blue leaves. Plants will reach about 6 inches (15 cm) in height and will spread to 2 feet (60 cm) wide. They produce root-like rhizophores along the weak stems and are easily fragmented. They make great plants for hanging baskets or as a ground cover in the landscape (hardy in USDA zones 6-10). *Like other members of the genus Selaginella, common names with the word 'moss' and 'fern' are misleading; they are part of a quite distant ancestral line belonging to Phylum Lycophyta. Blooming: Selaginella species are spore-producing plants that are frequently referred to as "fern allies." This group however separated early from the ferns and is much closer to lycopods and quillworts. These do not produce flowers but form inconspicuous cones (or strobili) 0.4 inch (1 cm) long and distinctly 4-keeled. Culture: Selaginella uncinata is very easy to grow, only requiring a rich moist soil and shade. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 1 part loam, with small pine bark added. The plants are grown in at least 50% shade at all times and plants are kept moist. They respond to light fertilizer applications on a weekly basis with a balanced fertilizer diluted to ½ the strength recommended on the label. During the winter months, we maintain this species in cool rooms in which the temperature runs about 45°F (9°C) at night. Water is somewhat restricted, but the plants are never allowed to dry thoroughly. Propagation: Selaginella uncinata is propagated by division of large mats or by stem cuttings. Selaginella uncinata was featured as Plant of the Week June 2-8, 2006.

You might try the fern forum. This forum is for plants native to North America. You could also try the name that plant forum and that forum accepts small attachments.