First I apologize for the bad pictures. Some reason the camera is hating any fake light and today there is NO natural light from outside

what a gloomy day outside!! I tried my best and took a good 30 pictures and finally gave up...
So the black lining on his tail (not fin rot or anything!) is breaking away to make way!

He doesn't look like a roundtail anymore. I have never seen a betta's tail grow or anything, other than Crayola's but his was length, nothing more. His is getting WIDER... along with the black is breaking away to make way for it to be longer.
So, now I dunno

although it is interesting to watch these changes take hold literally every day...