Question
Hello again. I wrote to you on 3/13 about the 2 fantails and 1 common goldfish in our pond (the pond had been covered with greenhouse plastic all winter) that had laid eggs and had managed to get themselves  stuck between the pond rocks. We thought they were in the rocks because of the eggs, but you said they were trying to rest and hide from the males after an exhaustive spawning cycle. We released the 2 fantails and they seem OK.
We found the 3rd goldfish, which is a common goldfish (not a fantail) and she appeared to be definitely stuck head-first in the rocks. We moved the rocks and got her out. She did not look good.
She had several areas of her body that were white and she she had lost her scales, presumably from rubbing against the rocks for so long. She slowly swam over to the other fish, but one of the males started chasing her again and she was trying to get away but seemed overwhelmed. (We thought she was being chased because she had been damaged or perhaps she still had eggs??)
Anyway, she was fairly easy to catch because she was swimming slowly, so we caught her and put her in a hospital bucket using water from the pond and put the bucket in our bathroom. She just sat there on the bottom of the bucket, her gills barely moving. It appears that about 1/4 to 1/5 of her body is missing scales. Most of the damage is on the sides and top with a small section near her tail. Her eyes and all her fins seem OK.
While in the bucket, we are treating her with MelaFix and Stress Coat and one very small amount of aquarium salt. She has an air stone for aeration and she gets daily partial water changes of at least 50% to 60% new water. I've been using the pond water for the water changes as that's what she's used to. I bring in 2 large jars of pond water at night and leave them in the room that she's in so the water temp will be the same when I do the water change the next day.
On 3/17, she started looking better and seemed to have her energy back and I thought she was ready to go back in to the pond. Then I noticed that she was getting black blotches on the damaged areas so I continued with the hospital bucket treatment until 3/19, which was Monday. She looked bad on Monday with the damaged areas getting black. It doesn't look like fungus (not cotton-like) so I thought she might have developed a bacterial infection. I went to the pet store today and bought some API T.C. Tetracycline and talked to one of the sales gals who thought the black areas might be new scales growing in and the new growth might be exhibiting a color change. I have not used the Tetracycline yet and won't if I don't need to but wanted to have it available if necessary.
When I got home, I went on-line to several fish-care sites (including yours) and found out about a condition called melanophore migration. I googled it and found out that it's a condition that develops because of damage or trauma - the good news being that if the black blotches are present, healing has begun. I believe the black/dark grey blotches are from trauma and not from high levels of ammonia.
How long would you recommend leaving her in the hospital tank?
Do the blotches need to be gone before putting her back in the pond?
Is using pond water for partial water changes OK or should I use tap water with some Stress Coat?
Do the scales actually grow back? I always thought the scales were clear and the color was on the body???
I'm feeding her 8 to 9 small floating pellets of food per day, and although I don't see her eat, the pellets are gone. Should I continue to feed her?
I'll continue with the daily water changes as I'm worried about ammonia, but I do have some AmQuel.
Any advice or experience you have with this would really be appreciated. Thanks for your help and all you do.

Answer
Goldfish can sustain pretty good damage from spawning.  I've seen fish damaged pretty bad that recovered ok.  It sounds like you're taking good care of her.  I suggest using tap water (with dechlorinator, salt, and MelaFix) for the water changes.  Pond water has a lot of bacteria in it.  Healthy fish can fight them off but she is damaged.  Cleaner water will help her heal.

The black areas are normal for fish healing from injuries.  The black is dead tissue.  It is a GOOD sign that she is healing.  Antibiotics are a good idea for fish with bad injuries anyway.  The black areas are not new growth or new scales.  I would treat her with some antibiotics as long as the quarantine bucket is comfortable enough for her.  Tetracycline may kill good bacteria but if you don't have a filter in there, that's not relevant.  High ammonia can cause black spots from burning but as you say, I see you found out about the black spots meaning healing (I just read that).  I once kept a damaged female in a 5 gallon for two months, and she never completely healed over. It takes a long time.  I normally leave damaged fish in the pond due to lack of my time.  For your fish, I recommend two weeks minimum in quarantine.  She has to be strong enough to keep the boys from beating her up!  The blotches don't have to be gone before she goes back.  The open areas where she was cut may turn white but it should be a healing white color which I can't describe and not the white from infection or fungus.  

Yes, use tap water with Stress Coat for water changes instead of pond water as I said before.  The scales will grow back but it will take months.  There are multiple layers to the scales.  I've seen scales that have come off, and they had some color.  I think color can both both on scales and under them.  If the pellets are gone, she either ate them, or they fell apart.  You should feed her.  I wish I had more time to give you more tips but I've got a ton to do so off I go!  Good luck!