Is there such thing as a SG Shock?

[Seek828]

Hey all,

I just got a new book call "The Marine Fish Health & Feeding Handbook" by Goemans & Ichinotsubo.

Its a pretty good book so far with lots of great insight.

There is one point, however, when the authors talk about acclimation techniques that quite confuses/worries me.

In a quick summary, the authors are basically trying to say that new fishes are better off being quickly release out of the bag and into good water instead of going through slow "drip acclimate" technique, especially if they have not been in transit for too long, say less than 2 hours. They basically say if the temperture is close enough, add the fish into the tank right away, and if the temperture is quite different, then just do the floating bag technique for no more than 30 minutes, then release the fish.
I pretty much agree to this point.

The authors then go on to say that they recommend the SG of the QT be around 1.010-1.013. (For fish only, of cause)
That too I understand this with the whole hyposalinity idea.

The thing that I don't understand is,
Isn't there such thing as SG shock? Similiar to a pH shock or temperture shock when they are changed too rapidly?

I used to think so and if there are indeed problems with SG shock, how can I keep my QT at such low level of SG and then drop my new fish, which likely came from SG of at least 1.019, if not 1.025, from the LFS, straight into the QT? (Even after equalizing the temp.)

Also, what happens when I bring the fish up to the display tank when quarantine is done?

I currently keep both my display and quarantine tank at 1.025

I am really tempted by the idea of keeping my QT at such a low SG at all time since I have been having some problems with parasites, namely ich.
But this is kind of worrying me.

Any comment would be great!
Thanks!!