we put all new arrivals in a quarantine tank. Upon arrival, they all seemed healthy ( no fin rot) but didn't eat. After a few days of acclimating to the tank we treat all new arrivals with prazipro. After completing the prazipro quarantine, they all began to eat and we noticed the choirs wrasse had fin rot on his pec. We did a 50% water change and I was not around for two days.....had no choice. The choirs was a lot worse, the naso had some on her pec and the tusk had some on his tail. The wrasse got progressively worse quick in 2 days and dropped. We then did a saltwater dip with para guard with the naso and tusk. They both didn't respond well. We reintroduced them back to the quarantine tank. After a few days with no meds, they began eatting again. The tusk ate frozen shrimp and the naso nori.....any idea what the cause of the fin rot was?... The specs on nitrate, nitrites, ammonia, ph, temperature.....are great. They are all swimming and have some appetite. The naso, after the dip, got a patch on her side, like a little,lighter than her normal color., about an inch round. It is not peeling or slimey. She did not have it before the dip and it is not progressing....we did introduce para guard today. So within the last two weeks they were given prazipro and now para guard. We will see if there is any improvement tomorrow.