My Koi fish was attacked by a Blue Heron about 2 months ago. I chased the Heron off and it dropped the fish. I put the fish back in the pond but it had a couple of puncture wounds. It is still alive, but stays mostly on the bottom and when it tries to swim, it is kind of on its side and goes in circles. It also has difficulty getting to the surface and cannot stay there more than a couple of seconds before it sinks to the bottom again. I have been hand feeding it every day to keep it alive. It will hungrily take the food from my hand if I put it up to its mouth, but can't feed itself otherwise. Is there anything I can do to help it heal, or is this all I can expect? I have seen no change after two months.
To treat wounds on koi you can use surface painting(aplying it directly on the wound of your fish)this is first aid to your fish to avoid infection of the wound in addition to this you have to make sure the water parameters are good to be sure you give the fish the best chance of surviving.
You can buy potassium permanganate solution in any Pharmasy and use a q tip to aply this directly on the wound of your fish,using this is the best solution in my experience.
potassium permanganate is a powerfull antibiotic and anti fungal remedy and it have a natural part in every first aid kit for both human and for use on pets.
if you do google potassium permanganate you will find lots of information about the use of it,every thing from desinfecting garden ponds to treating wounds in people and pets.
Very little can be done if it is an old wound but try Talking to a vet and ask if it is Possible to put in an suture to close the wound,try to keep an eye out for signs of Innfection in the wound and try to keep the Water parameters as good as possible.
I had a fish do that after hitting a rock. Sounds like the swim bladder was injured. He lived a couple years just fine but then a blue heron showed up :(. He was easy prey since he liked to rest on top of the rocks because he couldn’t float. So just keep that in mind for protection. Now this morning, my favorite koi was injured by a heron. It dropped her but she has a big injury. Trying to research what I can do for her. She seems to be swimming ok right now but only time will tell.