Oh no, I'm so sorry to hear that 

This is more of a comment than advice maybe some of you know the right answer,but I have kept goldies 20 years w moderate sucess maybe I will say some thing of value!
I have noticed at times the tail fin showing red capillaries,looking kind of glassy and ripply.(is there such a word?)
I was told by a true expert,That as long as the fin isnt ripped or disentigrating this is a normal growth thing for the fish. I dont know if this is true?!  He also stressed SALT!  I use half a tsp per gallon-I was suggested to raise it to a full teaspoon.  My fish hardly ever get ick w 1/2 tsp.

Also what SALT do you recommend-I use GOLDFISH, or AQUARIUM salt from the petsore.  But I see Epsom salt also being recommended.  I have used SEA SALT from the grocery store. Well, its healthier for my family, so is it healthy for my Goldies?

I use normal sea salt whenever that's needed, epsom salts is a completely different chemical and is used as a muscle relaxant or laxative when treating goldfish with dropsy, constipation or swim bladder issues.

Once you see the diluted blood vessels in the tail, you'll know the difference between that and visible veins in healthy goldfish One of my orandas was showing these, it almost looks as if there's dried blood between the rays in the fins. I also have a really old tancho fantail who has pretty prominent but healthy-looking veins in the tail.