Andy, this is what Dieter told me, email, on the subject of ammonia poisoning. The breeder says the dorsal damage was caused by stress.
Do you think this stress theory is possible? At present, I am not treating. Would you? The medication mentions is not available in the US. I think it may be similar to KanaPlex.
“Ammonia poisoning can only happen in the transport bag if the pH value is above 7.5. However, this is not possible because the fish exhales carbon dioxide, which forms carbonic acid in the water. Normally, the pH value in the bag is below 7 and the ammonia is present as harmless ammonium. Even high concentration with more than 100 mg of ammium do not poison the fish, when pH is below 7.
I think the fish has an infection of bacteria or Ichthyobodo necator. Apply a bath with sera omnipur over 7 days.”
Best regards
dieter UNtergasser