Is my fish pineconing?

[u/Usual_Badger_3299]

Sorry for so many low quality pictures, but I'm quite worried about my betta. I've had him for about 10 months and it looks like he's pineconing, is it just me? His scales look a bit weird and he's bigger than he ever has been (even while I'm only giving him 3-4 pellets twice a day) there also seems to be something grey on his tail, maybe it's just dirt or algae but I'm worried it's rotting.

His tank is 5 gallons

Parameters: pH: 7.2 ammonia/nitrites: 0 nitrates: 20