Fantail behavior in pond

Question
I just went through my second winter with a small pond.  I have a comet and
a fantail that are about 4 inches long and baby fish that were hatched last
spring. It got cold enough to ice the entire pond except where the pump was
working. I noticed that my fantail was lying on it's side at the bottom of the
pond and seemed dead but if I poked at it  she would move around. It is now
spring and the water temp is beginning to stay in the 50's and the smaller
fish are swimming around but the fantail is still just laying on her side. I
noticed today that here were some black spots on her belly area . Could she
be sick? I can see one of the smaller fish is now doing the same thing, but no
black spots. The rest of them ( 10 ) are acting normal. The comet is hiding in
the black tubing I have at the bottom but seems to swim around normal when
he comes out when I force him out. I have a two pumps. One in the pond and
one outside. I do water changes and treat the water with Clear-Zyme
Concentrate. The ph is at about 7. My pond is 169 gallons. The fantail did not
have any trouble last year. Please let me know what might be going on and
how I might do treatment if necessary. One more thing..I gave the fantail and
the small fish a salt bath for 10 minuets and put them back in the pond. It
didn't seem to help. thanks for your time.

Answer
Hi Karen
It sounds like there might be some sort of parasite at work.
It is hard to say exactly what without seeing the fish, but salt bath is certainly helpful. I would repeat it several times a day and you may even want to increase the dosage a bit.
The other thing to try would be to treat the entire pond with a broad spectrum parasite treatment available from pond dealers.