Koi behaving strangely

Question
I have a small garden pond, about 700 plus gallons.  It is app 43" deep at the deepest and recently my son and I took it apart, (blanketweed) cleaned it, dug out some shallow ledges for bog plants and some more stable ones for deeper plants.  I have one Koi, who seemed totally content previous to the clean.  I have not replaced any plants (just have not found any yet) but do have an aerator and a pumped stream of water to help with oxygen.  I run a dual type filter, both particulate and biological and feed floating pellets tubifex worms and flake food.  I have app a dozen smallish to med goldfish who seem happy as well... now to the problem.  The koi lays on the shallow ledge and sometimes is partly out of the water.  No damage to the fish that I can see, swims just fine if startled back into deeper water and eats normally.  Any ideas why he is doing this?  I really am attached to it and would hate to loose it at this point.  Thanks for your help

Answer
When you dug out the pond more, I assume you removed the liner?  Did you then reseat the same liner over the hole?  Regardless of that, the whole thing was probably very stressful for the koi.  Where did he go while you worked on the pond?  Could he have been hurt when moved?  Hanging out in the shallows could indicate that he was hurt.  Other reasons would be because it's warmer there, or he can garner more oxygen there.  Did you add dechlorinator when you refilled the pond?  If the goldfish all seem fine, and you've tested your water quality and see it's fine, then hopefully, the koi should recover from whatever is bothering it. Also, hopefully no predators will find him while he's there in the shallows.  Your description sounds okay, nothing obviously wrong.  Good luck!

Robyn
fishpondinfo.com