Nursing a struggling fish

I recently received some darters from a local yahoo that seem to be struggling a bit. Perhaps you've experienced this before.....that moment of panic when you notice one of your fish "wasting" away. You've been feeding regularly and everyone is healthy - including individuals of the same species, but this one fish seems to be struggling. You know it's not old age - and nothing APPEARS to be wrong externally, but the fish is in trouble. It may or may not take food. If it does, it often seems to spit it back out.

So, the question is, have you been able to reverse the "wasting" trend? I am trying some new techniques, such as feeding various live foods and quarantining, but was curious if anyone else had thoughts on this.

Jeff

Your fish may have internal parasites, or irreversible organ damage. I think quarantining the fish is definitely a good precaution.