oddly behaving black moor

Question
Hi Ron,

I have a black moor that for the past three/four days has been floating up on his side. He has randomly been coming down to swim around at times and when I feed him, but for the most part has been getting worse. I placed him into a "sick tank" yesterday and did not feed him (he was getting picked on by my other/bigger black moor). I thought that he died because it appeared that he had stopped breathing for the majority of last night, but he was alive and started swimming again.

I looked under his gills and they appear deep red, and his outer lips also look somewhat pink? I've also noticed that his eyes have become greyish/cloudy lately as well (over the past month or so)?? I tried feeding him again, and he still ate a little, and since then has been swimming around more, and no longer has been floating on his side??

As far as my regular/non-emergency tank, it is a 40-gallon tank. It has been up and running for 3 years now and has an AquaClear 70 gallon filter. I just tested all levels (pH, nitrate, nitrite, and ammonia) and all came back regular except my nitrite was at 10. I did do a 30% water change, but my other fish (a black moor, ryukin and plecostomus) are all fine and well.

This fish is probably currently three years old (since I have owned him). I am not sure if it is safe to put him back in my tank now and that maybe he was just stressed from the big guy picking on him? Or that it may be something more serious or just old age?

Thank you for your advice and help!

Sincerely,

Deanna

Answer
Hi Deanna,
 It sounds like he was being attacked by the larger fish.  As such, putting him back in with the big fish may not turn out well.

-- Ron C.
  rcoleman@cichlidresearch.com
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