Clown fish fin rot?

[Ytsejam02]

My clown looks like he might have fin rot. He's behaving normally, eating ok and such. Water parameters:

0 ammonia
0 nitrites
0 nitrates
0 phosphates
8 dKH
440 calcium
pH 8.05

It's with another clown that's half its size, and he usually nipa at the other one, not the other way around. No other fish.

Thoughts?

http://uploads.tapatalk-cdn.com/20160709/d68ac0fc54802bc58ff5bf73a6ba79ce.jpg

Sent from my XT1585 using Tapatalk

[Ytsejam02]

Anyone? Does it look rot? If the picture clear enough to tell? It doesn't seem to match images online, but I can't think of any other reason for the recession.

Sent from my XT1585 using Tapatalk

[conjuay]

you might want to repost this in the 'fish disease' forum.