pahansen
Fish Fanatic
You might want to consider testing specifically for ammonia, rather than just for nitrate and nitrite, just in case. In another thread on the Chit Chat board, some more-scientifically-minded-than-me people were explaining how your tank can read 0 for nitrites, high in nitrates, and over-the-top for ammonia, just because the chemical reactions can't keep up with the ammonia load. I have no idea if this is the problem with your pleco (indeed, I would think that if ammonia were high more fish would be exhibiting odd behavior), but it's worth checking just in case.
The link to the thread is http
/www.fishforums.net/index.php?showtopic=78913. There is a particularly interesting post by Bignose, about 2/3 of the way down the page.
Good luck,
Pamela
The link to the thread is http
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Good luck,
Pamela