I'm wondering what this is on my panda cory, iv'e had 2 die in the last week for no apparent reason and this one has not really been moving for the last day and i'm pretty sure he's sick but don't know whats wrong. I've had fish flashing as well as one of my pandas so dosed with prazipro a week or so ago. As a precaution I've been doing 50% water changes every other day as I seemed to have killed off my beneficial bacteria. I just went and looked and now he has this white stuff on him. What is it and what should i do?