If you hadn't lost your angel yet. Might wanta try aquarium salt and heat. Mine were covered in white just like yours. After I lost 4 out of 6 the 2 I have left are doing amazing after 2-3 days. Nothing else worked. My heat was on 87 degrees steady and in a hospital 10 gallon tote with a tablespoon on salt. Make sure you let the salt dissolve in a bowl at water change time. Add it to the tank water and leave it there for 2-3 days and vacuum the bottom when you start seeing less white spots. I pulled my fish out when I didn't see anymore. And put them in a different tank with clean water and another salt treatment. This seems to be working for me. I also feed them pebbles soaked in garlic juice most days. Good luck!