Pond goldfish and fungus

Question
QUESTION: My 1100 gal. pond has 4 goldfish, all infected with some sort of fungal disease: white, cottony, stringy.  They originally had ick.  I removed fish from pond, treated, drained pond, reintroduced fish.  Now this fungus disease has attacked.  I am in Mexico, with limited fish medicine availability. If I just remove and euthanize the 4 fish, does the fungus disease remain in the water?  Any advice?  Many thanks for your time!!!

ANSWER: Where on the body is the fungus?  You can treat them with salt and diet to see if they improve.... let me know dave

---------- FOLLOW-UP ----------

QUESTION: Fungus is on the flanks.  I first noticed a pustule on one fish about three weeks ago, shortly after ick treatment.  Tried to catch him but couldn't.  My pond is planted with bog plants and water lillies thar cannot be easily replaced.  What dosage of salt should I try?  What sort of diet?  Aquarium salt here is sold in tiny 3 oz. bags WHEN it can be found.   Repeat:  if fish die, does fungus/bacteria remain in water?  My fish are fantails. I know I should have started with shubunkins but could not find any.  Many thanks, Dave!

Answer
There is fungus and bacteria in the water and it is naturally occurring.  The problem here is that it appears the fish has a lowered immune system.  You can boost him/her immune system through diet with brine shrimp, tubiworms, and even algae wafers.  Some prepared food will also help to boost the immune system of fish. Such foods will usually indicate vitamin enriched, etc.  Rock salt will help too... though I do not recommend this in your pond because it will kill off or damage the plants.  The same is true of aquarium salt.  It is likely that the fish will recover and be just fine.  Keep me posted.. dave