Im so frustrated and defeated, I feel like I shouldnt even keep fish anymore. I had a lavender tang and sunburst anthias in quarantine for a month with coppersafe. They were all doing fine and eating great. As usual with my QT regimen I stop copper, do 1 week of observation and then treat prazipro. I know about the tendency to deplete O2 so I had 2 airstones and a powerhead churning the surface. I started with half a dose of prazi and would put the other half the next day. Both fish died within 6 hours of eachother. They started off fine and then one by one Id find them on their side breathing heavy. Gills were not pink or inflamed from what I can tell. I dont know if the prazi O2 depletion did them in or if they all had so many flukes that once they detached they bled out. I lost 2 fairy wrasse the week prior in QT under mysterious circumstances as well. They were in a 5 gal QT bucket with an airstone, heater, and powerhead. I always make sure the surface has alot of agitation and they died in less than 24 hours. RO/DI filter has fresh filters on and the fish are fine in my DT. I think Im done using Prazi and will try hyposalinity for flukes in the future.