Even though I've had my Koi pond for over three years now I still feel kind of new to it since I really inherited it from the previous owners and did as much research as I could about maintaining the pond and such. But I have little experience with disease.
The pond I have is about 250 gals, one of those preformed black plastic jobs, buried in the ground. I have a pondmaster filter that drives a fountain and a waterfall. I have been using pond pads to keep the water clear, and regularly checking the pH, ammonia, nitrate and nitrite. The pond has pretty good tree cover and does not get an excessive amount of sunlight. There are four goldfish and one large Koi ( about a foot and a 1/2 ) in the pond. They are all original, I have not added any fish to the pond. I do not have any vegitation in the pond either.
I did notice a small spike in nitrate and ammonia levels recently, nothing enormous; I thought I might be overfeeding with the huge temperature swings we had lately.
While doing a water change today I noticed that the Koi had a scale hanging off of it ( about the size of a 50 cent piece ). It was behind the petoral fin closer to the tail and near the bottom of the fish, it just seemed to flap around as the fish moved.
The Koi has a healthy appetite and does not show any other signs of strange behavior, although it has been knocking over the fountain a few times lately ( it has to be the koi it is easly 3 times the size of the other fish ).
Other than checking the water quality and salting the pond, is there anything else I should be doing and looking for??
Thanks for the help.. Nice to see this forum is here, I frequently buy from Ned's and stop in for advice; but can't always get down there during the week.. Thanks for putting up the forum..
~Scott