Sick goldfish

[max384]

I bought twenty feeder comet goldfish and put them in a pond that had only been filled with water for 48 hours (I know, unwise, but live and learn). Two died within hours; one looked normal, the other had a kinda fuzzy-ish white spot on him that looked more like an injury. I've been keeping an eye on them and I noticed that several more fish have these white spots on them. It's fuzzy and looks like pictures of fin rot I've seen on the internet such as this one:

(^^^^Not a picture of my fish, this is one off of the internet that looks similar)

However, it's not confined to the fin; it's also on the body as well.

Here are some pics I took (best ones I could get):

I'm leaning toward a fungal infection. What do you guys think?

What do I do to treat it?

Thanks.

Oh, and last night I tested the water and found:
nitrate: 0
nitrite: 0
Hardness (GH): 75ppm
Chlorine: 0
Alkalinity (KH): 0
pH: 7.2
Ammonia: 2.0ppm

This morning:
nitrate: 0
nitrite: 0
Hardness (GH): 75ppm
Chlorine: 0
Alkalinity (KH): 80
pH: 7.2
Ammonia: between 0 and 25ppm

Just now:
nitrate: 0
nitrite: 0
Hardness (GH): 75ppm
Chlorine: 0
Alkalinity (KH): 40-80
pH: 6.8-7.2 (mine goes by 0.4 pH increments)
Ammonia: between 1 and 2ppm

 

[stroppy]

water changes to get rid of the ammonia would help ...looks like fin rot salt might help but i dont no enough to help much hopefully someone else does

 

[fishin4cars]

I posted on your other post where you showed the pics. You tests are showing something really goofy going on. Your alkalinity shouldn't be bouncing around like that, it should be staying about the same just like the GH. also, your ammonia readings aren't right, 2.0 is deadly I could understand it going that high to cycle, dropping down to .25, fast drop with out water change, or adding something that would help remove the ammonia, then it jumps right back up, jumping back up makes me think look for a dead fish, or left over food. if you find food dead fish, anything that is rotting and decaying try and get it out. this is all normal. the fungus is from the high ammonia, I'm pretty sure. The one water condition that really bothers me is the alkalinity. it can cause the same effects as ammonia but the jumping from low to high has me wondering why?