santoury;1135097; said:If you consider darkening a "burn " Then look no further.
Ammonia can cause the opercular areas to turn a deep red, sometimes violet/grayish. Sorry dude, but it's not so much a hoax.
It could depend on the consideration just like you said.
But without any evidence it still is just a laymans metaphor leading to misunderstanding!
For example:
http://www.goldfishconnection.com/articles/details.php?articleId=143&parentId=12
The point about healing might be correct and can be substantiated for example by:
Ronald J. Roberts
"Melanin-Containing Cells of Teleost Fish and Their Relation to Disease"
in
Ribelin&Migaki
"The Pathology of Fishes"
University o Wisconsin Press, 1975
But what causes the healing effect???
There we are with superficial layman-conclusions.
The fishes skin might be healing because of high ammonia-stress-level caused by import conditions or it might be stressed by rough netting ...or they might not, who cares...
Just unproven claiming....confusing hobbyists!
So does anybody know something about it with any evidence not being based upon laymans-logic?
By the way there is nothing as easy as disproving unproven claims, if the fishes of that importer really turn that black he is a poor importer who should find a more reliable breeder and if fishes turn black caused by ammmonia (as it is already pointed out) the keeper is a poor keeper (and the fish would already be dead caused by gill hyperplasia)
So it seems to be more obvious that fishes (in this case Goldfishes especially) turn black caused by a delayed stress syndrome, leading to an energy-deficiency-syndrome (see: Selye, Hans; The Physiology and Pathology of Exposure to STRESS ACTA. INC. Medical Publ., 1950)...finally leading to death just causing darkening as a symptom in parallel.
Can you catch me?