tank parameters are ammonia 0, nitrite 0, nitrate 20, salinity 1.024, PH 8.4. those are all the tests i have. i haven't sprayed anything in the house recently, so i am pretty sure it is not that. however, i did just recently start running my tank open top instead of glass top. not sure if that might cause a problem. they fish were definitely scratching themselves, they had larg spots on them where all the color was rubbed off. so the parasites can't live dormant on the lr or on the other critters right? thanks for the replies btw