Hey how is Indigo doing? Heavy breathing and darting it can be external parasites or gill flukes. Is it also looks like he want to rub his body on objects? Both can be treated with aquarium salt if treated on time though.
Is he still with you?
First keep him in dark no light since they will spread faster with light.
If you can raise the temperature 84*? It will help to speed up life cycle and fall faster so you can remove them manually from the tank when you change his water.
Pre mix 2 tsp aquarium salt in one gallon make sure it dissolved or in the cup if you don't have a gall. Make daily water changes .
Do you have hospital tank? Or take clean small container where you can keep him because i don't think it possible to change 10 gall daily.
Also if you have another fish don't share anything between them.
What do you have in his tank? You will need to disinfect every thing and it easy with parasites. You just need to wash it with hot water and dry out for a few days. Parasites die without host.
Do you have live plants in the tank? I will also tell you what to do with plants.