You've done everything you could to treat a bacterial infection.... Want to try treating for internal parasites? IMO, it's worth a shot. It sounds like she's trying to fight this thing.
API General Cure (Metronidazole and Praziquantel) is a good antiparasitical medication. It treats the majority of aquatic parasites.
Some people have had good success soaking pellets in the General Cure, too. Soaking the food brings the meds internally, which is where the parasites are located.
I know it can be used with Kanaplex, Epsom salt and the furan antibiotics. I'm not sure if it can be used with tetracycline, but I don't think it will pose a problem. (I'll try to find info on this.)