neutered pup, coat still silky, any way to prevent going woolly?

[Tiramisu]

not sure where's the best place to put this....

pup is now 8 months old pretty soon, he was neutered around 2 months ago, the coat still lovely and silky...
many stories that the coat goes woolly..... but he's neutered already, no way back..

so any suggestion on any way to prevent his coats go woolly?

he's now on fish diet! hopefully will be better........