Alright firstly like bettagurl said, he is a crowntail... crowntails are sensitive to water quality, poor water quality will cause their spikes to burn off you could say, high ammonia in water will cause them to lose the spikes which is definatly what happened to your guy. And he definatly has finrot, look at the brown edges. Now as for the white fin/scales, there's a possibility that it could be early stages of colmunaris, but if after treatment (meaning good treatment such a a mix of maracyn 1 & 2) the white is still there, its not fuzzy and doesn't seem to be spreading then there's a chance that he could be marbling out. Some bettas will marble later in life, and a marble betta is constantly changing, even if its very small unnoticable changes. Hope that helped.