No other signs of a parasite attack? It could make them flash.Just a thought,
3 days ago I noticed a sore on my large koi, today there is one on another
koi. Both koi are white females, one a butterfly. Both are about 20"

no, I thought about that also, and gave all the koi in the pond a really good
look.....on the colored ones I probably couldn't tell, but on the other whites
and yellows no other sores,,,,just those 2 fish Jerri

http://www.fringeweb.com/Ponds/JerrisPond