how fast for ich to appear?

[astroboy]

I bought a powder blue tang a couple of weeks ago from a reputable source who claimed they had the fish in their tanks for three weeks and it looked great the whole time. When I bought it, it did look fine and I've had excellent luck with this source before, for corals and fish.

 

I put it into a quarantine tank, which used to be my display tank so it has about two inches of substrate in it and a few chunks of live rock and a a few snails. My point is that the QT is hardly a sterile box, but I did have clowns and six line wrasses in it for over a year without any signs of trouble.

 

After 36 hours the tang had a bumpy skin and very small white dots. In my experience, the dots were much smaller than what one normally sees with ich. After 48 hours, the dots and bumps went away, and the fish looked great, but they returned five days later and the fish was dead within a day.

 

My question is, was it possible that the fish got infected with ich (or velvet?) from my QT? As I understand it, it wouldn't be possible for either disease to show up in less than two days after the fish was initially infected.

 

I'm guessing that the fish was infected when I bought it but was doing OK, and the stress of moving caused the infection to break out. Still, that would mean that the stress kicked the somewhat dormant ich or velvet into the stage where it enters the trophont stage almost overnight.... Is that possible?

 

Any recommendations on how long I should let the QT lie fallow, assuming the disease actually was ich or velvet?

 

Thanks

[JR-Tanked150]

it's 8 weeks for ich, don't know if it's the same for velvet.

[freshfins]

The timing depends on temperature.  The warmer it is, the shorter the cycle is for ich.  You can kill it off from your tank faster if you raise the temp to 90+.

[Coral Hind]

The whole life cycle can be as short as seven days from first infection until the next generation infects again. Once the fish is infected it can start to show the signs of ich on the surface in just two days as the trophonts break the surface to begin the free swimming stages. Between days 3 and 7 they drop off to settle into the substrate to reproduce. The tomonts or cyst stay in the substrate for 3 to 28 days before release and reinfection of the fish. So yeah it could have gotten ich from your QT tank if it wasn't properly cleaned before the fish was introduced.

 

Was the fish just observed at the store or was it medicated as a preventive measure? If just observed then it might have had ich on it before you brought it home. If it was medicated properly at the store then it probably got it from your QT.

 

http://www.chucksaddiction.com/ich.html

[Coral Hind]

The timing depends on temperature.  The warmer it is, the shorter the cycle is for ich.  You can kill it off from your tank faster if you raise the temp to 90+

You could also just drain it, wipe down with bleach solution, fill with freshwater to rinse, drain and let dry for a day or two, then restart.