My husband's Discus have been suffering from "Hole in the Head" and "Lateral Line Erosion" for several months. We've tried all sorts of treatments, to no avail. In the past, we'd had one or two come down with it and we'd pull them out of the tank and treat them with raised temperature and metronidazole until they got back to eating and looking well. This time, it's all of them. We've lost several of the larger ones. The tank has an automatic water change system that swaps out about 10-15% of the volume each day, plus we do large water changes (60-70%) weekly. The water source is Montgomery County tap, which is moderately hard (higher GH than KH) The discus came from Hans and the other fish in the tank, cichlids included, seem completely unaffected. They get a home-made food mix that contains a small amount of beef heart, shrimp, freeze dried krill, freeze-dried soldier-fly larvae, Vita Chem, fruit, spinach, and a variety of prepared, high quality, pellet and powder foods. I started making their food about a year ago because I felt he was relying too heavily on beef heart and blood worms. Symptoms include flashing/scratching, holes forming in fins and the body (near anal fin), swelling and what almost looks like pimples behind pectoral fins, plus the typical symptoms associated with HITH/LLE. Treatments tried over the past several months include: * Proform- C (improvement for about 1-2 weeks following completion of treatment). * General Cure (Praziquantel + Metronidazole) * Metronidazole in feed * Angels Plus Red and Orange antibiotic flakes * Fenbendazole (Safe Guard) I always give a couple weeks (at least) between treatments and observe symptoms during and after. While Proform-C had some impact, it wasn't lasting. It's a tough treatment to do on a 300 gallon system this time of year because my hot water heater does NOT hold up to 75% water changes on the tank. I'll probably try Minn Finn next, as I'm wondering if this is the result of some sort of resistant fluke. I did borrow a microscope and have been planning to try to do a scraping of one of the more drastically impacted fish, but I'll openly admit I'm not very good with a microscope and I've had trouble finding the time/space to get it set up where it won't get knocked over by my kids. I honestly hate discus, but my husband loves them and every time I suggest we not get any more he pitches a fit. What I hate more than discus is watching fish die. I'm fortunate that I almost never deal with illness in my own tanks, but his tanks are enough to make me want to leave the hobby some days. Does anyone here have any thoughts on trouble shooting this, or even just experience dealing with it/the ability to commiserate?