tail deterioration

[FriendToNemo]

my clownfish's tail looks like it was cut or deteriorating I'm not sure whoch so I was wondering if you all might be able to depict which it is it looks white around where it is and there anemone was sadly lost to the powerhead we think because it was all shreded into bits when we woke up two days ago and I thought that the clown might have been injured then but now I'm begining to worry if it os deteriorating.
please help

 

[stykthyn]

the water quality may be suffering due to the anemone being killed. it almost sounds like fin rot which is caused by malnutrition or poor water quality. How much of a water change did you do after the anemone was killed? What are your parameters? Can you get us a pic?

 

[FriendToNemo]

I checked the parameters last night and my P.H. was very low it was about 7.4 and the amonia was at 0 and the Nitrite was at .25. I cant remember what the Nitrate was at. My protein skimmer is running and skimming very dark skimate. The clowns this morning have it on there sides and the little clown (male has it on his one side). Im going to talk to a LFS today to see what they might be able to tell me and im going to do a water change. They are hosting in a torch coral and there is another anemone that they show no interest in it. The torch coral couldn't do anything could it? And also as i looked at it closer today the tail looks like it has a coating on it almost the color of a star polyp its pinkish. It doesnt look like it is being eaten away. Its not ick though i know that.