so sorry. I was hoping he will survive. I have exactly the same cellophane betta . It was difficult to diagnosed from beginning though. I guess it too late since he sick from 2 weeks ago. But who new what it is....Not your fault. We all learning. And his parasites were different than the other people who i spoke to.
How is your other betta doing? Did you share between them anything? Net or containers when you change the water?
I actually texted Oldfishlady about you. Oldfishlady the one who everyone learned from about all those natural remedies. I still want to post for you and anyone who will see what she wrote me back.
You knowFresh crushed garlic taken by mouth in large enough amounts several times a day can also help both internal and external parasites but it can take about 6 weeks to be effective
For external parasites=this depends on what kind it is....sometimes the salt will not do anything for some external parasites-some have to be manually removed-the salt is usually used for secondary infection from the wound left by the parasite when they detach.
Natural treatment can be effective and often better for the fish, us and the environment, however, with some ailments it can be too late even for OTC...it never huts to try-but it is important to know what you are treating, understand the life cycle of the parasites when treating to be most effective.
You also need to rule out the environment and husbandry as a cause.....
Treatments are not always cut and dry or one size fits all........
Be careful with the products that have aloe vera-this can cause gill issues from build up.
I know Oldfishlady does homemade food for bettas.
If you share anything between Eros and other betta i would advice to try soak pellet that you feed your other betta soak in garlic juice just in case. See if he likes it.
I also wondering how Eros got those pirisites. The water is clean.I do the same water changes.
The only one think when i take care of my bettas i don't tuch anything. Even fosits . I always wash my hands and than rince under the water for a minat and than i don't tuch anything. I have no idia if it even matter thogh,