A very saturated solution of salt water will strip the slime coat off, taking many parasites with it, but it leaves the fish without the slime coat that is the protective layer between the parasites in the pond and the fish. I agree with Joey, that without a scrape and scope, treatment with Proform C or another formalin/malachite green treatment would be high on my list. The small wound can be treated with iodine and just keep an eye on it.
With the fish getting to the point of slowing down, I would do the treatments as soon as possible.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard