For my part, with such thick growth, I would wait until they are a fair bit bigger; sometimes, they selectively thin themselves out, and the weakest do not survive. In any case, when they are recognisably bigger, take a spoon, and carefully scoop 'individual portions' of ferns and transplant the spoonful to individual pots.

Bit by bit, the bigger they get, the easier they will be to separate.

I feel that they are too delicate to do that with, now, although it may not hurt to try taking some in this way, from the periphery, as an experiment....

Best of luck - wonderful result!

Hi, this is a very old post, I know. But my Adiantium gave seeds on the leafs and I want to plant them too. I wonder how your fern went after your post!

Keep in mind they're not "seeds" but spores. Ferns have a different reproductive cycle to flowering plants and you need to understand it to successfully propagate them. There's a lot of information on the web about it, try thisLINK.