I don't see the long parasites, just a normal tail for that variety of betta. I realize we're supposed to ask you to fill in the form, but I don't really think this post needs to be in Emergencies.
All they need is warm enough water 78-80 degrees F, good food like New Life Spectrum or Bug Bites fed at a rate of 3-5 pellets each feeding, two times a day, and reasonably frequent water changes (couple times a week initially) with Seachem Prime. Hold off on the rest of what you're doing, I don't think it's necessary.