My Large ZZ red FH lives alone an a 100 gallon bare tank. The water is heated at 82 degrees. (house A/c is set at 73) The PH is around 7.8. I've been doing 50% water changes every two or three days and I've been treating with Metronidazole.He has been again infected by ghost shrimp. He was once cured of this several years ago. This time, there's no end in site! He hasn't eaten anything on his own in at least three weeks. I've been tube feeding him. I've used EPSOM SALT in the tank and in his food. I've also recently started adding a trace of the met to his tube feeding. The feeding tube and syringe contain his favorite pellets soaked in water with a trace of met and a little garlic. He swallows about half and blows the rest out. I don't want to lose him. The meds say that you should discontinue use after ten days. He' not better yet. Any thoughts?