All of my fish have a nice size- my pandas are nice and plump, and my kuhli loaches have gained size in both length and width. But, one cory is extremely skinny. So thin, in fact, that he's being blown around by the current, helpless to right himself! My fish don't rush to the algae wafers I drop in like they used to, but I think that's because I may have broke the cycle for a little bit. I should be able to get a water test soon, but my last one read a little bit of ammonia. Anyway, they must be eating it when I'm not looking because it's gone in the morning, the fish are plump, and their fins are erect... except for that little one... also, his barbels are nearly worn clean off of his face! The others have slightly worn ones, but they seem to be the same, or growing back. What should I do? I don't want to lose him! Thanks in advance!