Beginner Gardening: Purple footed fern frond, 1 by BorisGarden

BorisGarden wrote:
Hello everyone, I've been looking at this website for years but didn't join until today, since I have a question that turned up nothing on google.

I have a footed fern, which has always had green fronds. Today, I looked at it and one of the new ones was completely purple. I don't know if it started out green or not, but many of them start out reddish or purple when it's just a shoot, and then have green fronds. But I've never seen any purple leaves like this. It looks healthy otherwise, no pests or anything I can see.

So, what is it? Some random mutation? I have two of these plants (from the same plant, but was divided) and this hasn't happened until now. I only bought it a few months ago, from a local nursery.

Anyway, not worried, just wondering if this sort of thing is actually a thing that happens, or if I've got some sort of exotic mutant on my hands all of a sudden, haha.