That tank shot puts things into perspective. You have a wide range of fry sizes in there, which isn't that unusual for nothos. Make sure those small fish are getting as much to eat as the larger ones. By the time the small ones are as large as the fish in the middle of the photo your population will need to be thinned.
That Java fern is probably reponding to the increased nutrients and water changes.
Was that largest fish the one with the blue on the gills? Most likely a male if so.