Fish acting oddly

Question
Dear Mr. Nesfield,

We have an 800 gal pond (outdoor) with 4 koi and some goldfish.  

This past Monday, we came home from work to discover that some of the goldfish were missing!  The koi were still there, however one is acting very oddly.  It is swimming in circles (both horizontally and vertically) and coming to the surface periodically to gulp air.  It is not eating (except by accident when surfacing for air).  This swimming/gulping action has been going on non-stop since then (it is now Thursday). We noticed that this koi has a scratch on its side and may have one on the top of its head.

We assumed that some creature has dined on the goldfish and tried the koi, but decided they were too big.   Do you have any idea what is happening with the koi?  Again, the other koi are behaving normally, although they swim to the bottom when we feed them.

Any insight would be appreciated!
Thanks in advance
Chris Graves


Answer
Hi Chris,
It looks like a cat has been at your pond as there are scratches on your koi and the one that is swimming in circles  I would asume that the cat has damaged it in some way and it will be stressed, if it continues to swim in this fasion I think to stop the koi from suffering it would be best if you put it to sleep.
SORRY I could not be of more help.
George.