The Alliance Veterinary Clinic in Bordeaux looked into the case of Emilie PSD's axolotl,
This one was losing weight visibly, regurgitating all food, including beef heart supposed to be much more palatable. His stools were whitish. His skin was peeling (he was losing his mucus). So suspicion of internal interference.
Here is the report from the vet who looked after Shadow:
Third day of treatment, to follow ...
Continued ... second visit ...
The flagyl treatment was stopped on 1/6/19 and the antibiotic as well as the anti-emetic the 9/01/19
Importantly, it turns out that the scaling did not come from Shadow's skin but from his irritated intestines.