sounds like your fish could have fin rot here is a picture of it
the symptoms of fin rot are
small holes anywhere on the fins
Fins that seem to be growing thinner or more transparent.
Fins that seem to be "fraying" around the edges.
Fins that seem to be breaking off in large chunks.
Slimey looking areas, usually on the tips of fins, that seem to "eat away" at the fins over time.
does any of this sound or look familer?
could you maybe post a picture of your fish so that we can better tell you whats wrong?