It may not be I'm not sure. All I know is that I have a fish currently that won't eat but he isn't bloating up, sometimes he hides but not as much as he did a few days ago before I put in the pennies but he's still not eating. I had a yellow lab. who acted like this for about three weeks and even though I treated the tank with an Anti Parasetic/Anti Bacterial medication he still didn't start eating and so I finally said screw it, better to get rid of him than to loose the whole tank of fish. so I flushed him about 3 days ago and everybody seemed to be doing well until yesterday and now I have a zebra doing the same thing. What can it be?