Koi carp problem

[willowman]

One of my Koi has taken to resting on a shallow ledge at the edge of the pond. It stays quite still and several people have asked if it is dead.
It's back is out of the water and is starting to get a white haze on it. If touched it will move and swim around for a bit, but then come back to rest in the same spot.
Has anybody got any idea what could be wrong with it?

[hammerman]

Koi love to sunbathe and i have a koi who will almost go into a deep sleep in the sun and like yours, it's back will stick out of the water and get burnt !!!.

Is the fish feeding ok ?....if it is, then you just have a lazy slob of a koi (lol). If the koi isn't feeding, you need to dig a bit deeper....start with having your water tested, are your filters blocked, is there enough oxygen in the pond. ???

[willowman]

Thanks hammerman.
The other koi are acting normally, which makes me think water is OK.
I inherited the fish when I bought the house. The filter is a large tank full of gravel, not like the modern stuff I see advertised. It keeps the water very clear apart from the inevitable blanketweed.
This particular koi has always been a bit of a loner, not going near the others, but it has never done anything like this before.
Trouble is, you can't just pop down to the vets, so I feel a bit helpless.