Goldfish scale loss illness question

[OneEyedBob]

Last weekend one of my goldfish looked like it was about to pass away. It had lost a lot of scales on both of it's sides. It is also missing chunks of various fins but I think that is due to it moving so slowly and the turtles probably chewing on it. This happened happened in the time span of a day and the fish spent the night hanging out at the bottom of the pond. I added some Melafix to the water, the fish survived and is now moving around great and eating. However, in the spots where the scale loss occurred there is not what looks to be black almost moldy looking fuzz on the fish. Any idea of what happened to the fish and should I be concerned for the rest of the wildlife in the pond? The fish is about 4 years old. I have attached videos and photos. any insight is helpful. I have scoured the internet and cannot find a photo quite like whats going on with my fish.

Thank You!

 

[Meyer Jordan]

For the present I would not be overly concerned as this may just be discoloration from the skin healing. I would recommend that you continue to monitor this fish fro any additional tissue damage.
I would never recommend that turtles and fish be kept in the same typical garden pond...entirely too small.

 

[AlyssaFish]

This is what I'd do if I were you: take the fish out, place in quarantine, treat with .3% aquarium salt solution. This will help the scales and fins recover, stimulate slime coat production to fight off parasites, mold or infection, and attack whatever is growing on your fish.

Monitor for signs of infection: bottom sitting, refusing food. Keep water quality pristine.

Additionally, I'd take a look at that stuff growing on him under the microscope to see if I could ID it.

 

[AlyssaFish]

For the record, looks like spawning injuries to me. Do you have a good balance of male and female fish?

 

[Faebinder]

The amount of damage looks too extensive to be just spawning. I'm thinking this may be a fungal growth. Isolation and salting the tank is your next step imo.

 

[DutchMuch]

The amount of damage looks too extensive to be just spawning. I'm thinking this may be a fungal growth. Isolation and salting the tank is your next step imo.

This is correct