It's great importance is reflected in the suite of designations to which it is subject, which include National Nature Reserve (NNR), Site of Special Scientific Interest (SSSI), Special Area of Conservation (SAC) and Ramsar (ascribed to wetlands of international importance). The fen is located between the villages of Capel Coch and Bryn Teg, and there is limited parking at Capel Coch.

A boardwalk leads through the reedbeds, and there is a track that enables access to other parts of the reserve. The fen has a variety of habitats including extensive reed beds, woodland, heathland and small lakes. The area is home to many specialised plants, like the fly orchid and the carnivorous sundew, and it hosts a rich assemblage of insects, especially butterflies, moths, damselflies and dragonflies.

The marsh fritillary, one of the U.K’s most threatened butterflies, can be found at the reserve, as can an isolated population of the rare southern damselfly. Dominant plant species of the fen include great fen-sedge, black bog rush, bog myrtle, blunt-flowered rush and purple moor grass. It is an internationally rare and important orchid-rich habitat, with a wide variety of species including narrow-leaved marsh orchid, northern marsh orchid, lesser butterfly orchid, and marsh helleborine. Rare stoneworts can be found here, as well as sphagnum moss and cross-leaved heath in the wetter areas. Other notable plants include marsh gentian, monk’s hood, and devil’s-bit scabious. The fen’s habitats attract a wide variety of bird life. In winter, you may see hunting hen harriers, or gatherings of lapwing. During the summer time, birds such as willow tit can be seen, and, if you’re lucky, grasshopper warblers, which are difficult to spot due to their camouflaged plumage and unusual ability to throw their voices! It’s also worth looking out for toads, adders, otters, brown hare, and water voles.