Caveden
I know that kanaplex can be mixed with Paraguard. I just don't know how a ray would react to using both. I have used both on a scaless South American Lungfish with no issues. The SAL was experiencing fin rot and the white fuzz progressing on up its tail like the white fuzz on your ray.
I wouldn't use the EIHO product until you can get confirmation from a ray keeper since it looks much stronger than Paraguard with the Active Ingredients for EIHO being Acriflavine, Malachite Green, Formaldehyde