Originally Posted by SWSCJ
I have 11 tangs. Ick = stress. The reef tank I keep at 77 degrees and have 3 cleaner shrimp and 2 fire shrimp that constantly clean the 9 tangs I have in there. My Vlamingi breaks out with ick every time I do a water change. I keep the water temp at 80 degrees and feed it heavy when it breaks out. I've had most of these fish for 5 years. Not one did I quarantine.
There is no dormant stage in the lifecycle. Ich does not lie in wait for a weakened fish to infect. However, any factor that reduces immunity like changes in water temperature and quality may, in a subclinically infected fish, accelerate an outbreak of Ich. The presence of ammonia, nitrite and high levels of nitrate in water does not in itself cause clinical cases of Ich. However, poor water quality will stress fish, allow an outbreak to spread rapidly and increase mortality rates in infected fish. Ich must be introduced to a tank per a host. Its caused by a Protozoa, it is not created in a clean tank. If your Vlaminigi is constantly getting Ich, I would think you would want to quarantine all your fish so that you alleviate the Ich in your display tank. Your tangs may have a strong enough immune system to fight it off now, but could change down the road.