How to prune Japanese painted ferns
Japanese Painted Ferns
Certified GKH Gardening Expert
Typically, you shouldn't have to prune these often. I would only remove dead or dying leaves. If you decided to prune it, I don't think you would hurt it, but you don't have to.
Here is some more information on care of the fern: https://www.gardeningknowhow.com/ornamental/foliage/japanese-painted-fern/grow-japanese-painted-fern.htm