Naso Tang Front Fins detonation

[robirwin1245]

Hi, I have a fish only 200 gallon tank with 250 lbs live rock 150 pounds live sand and a skimmer. The 5 inch nano tang front fins are about half of what they should be. I don't see him being nipped at any. So not sure what is causing it. Obvious answer is that he's being picked on but I don't see much of that - so was wondering if there could be another reason?

thanks!

R

[inurmind]

Sounds like fin rot...any changes to the system at all lately? How's it's coloration?