Paul wrote:

I have a large pond in the garden with about 10 fish. I noticed today
that I have a sick shubunkin. He is very lethargic, near the surface
and has a green tinge to his lower back that was not there before.

Should I fish him out and put him in a bucket with some salty tap
water?

Might zip out and get two 30 gallon or so Rubbermaid tubs, air stones, air
pump and some dechlorinator.

Make sure you dechlorinate the tap water before plunking the fish in it.
Salting the water (with fish salt, not table salt) starting at a
concentration of 1 teaspoon / 5 gallons working up to a concentration 1
tablespoon / 5 gallons over three days is probably the way to go.

Further treatment beyond isolation in clean water really depends on what is
wrong with the fish.

The following is a good place to go.
http://users.megapathdsl.net/~solo/puregold/home.html

Being ecumenical about things, others may prefer...
www.koivet.com

-Donald
--
"There is nothing so strong as gentleness, and there is nothing so gentle as
real strength." St. Francis de Sales