Getting a nice thick and fluffy fur and tail

Hi there!
I have a problem with my Maine Coon. He is about 4 years old and isn’t that big as his father. The first year after I bought him he had a really nice fur, his tail was very thick, width and fluffy. However, when he became approximately 1,5 year he lost that beautiful fur and fluffy tale. And he isn’t that big for a 4 year old Maine Coon.
Do you think this might have to do with food? I primarily give him dry food (every day) and now and then wet food.
And which food is best for optimum growth and to get a beautiful fur and big fluffy tail? I mean which type of food: dry of wet? And which brand would be best?


Thanks a lot for you help!

Noone? :'(

No idea, it could be anything. Is he pulling his hair off? Because mine had to go to the vet for that reason, she was probably overgrooming, just her tail though :(