no however dont use it for an extended period of time. Thats a general rule of thumb for ANYTHING. If youre using it to acclimate fish use it for the first couple of days (3 tops) and you should be fine. I havent really noticed much of a difference with or w/o stress coat at those levels on newly acclimated fish. I honestly only use it for chlorine/chloramine removal now or on my stingrays and thats it.
Stress coat frees ammonia bound to chlorine in chloramine, but it doesn't do anything to the ammonia, so the ammonia would be free to nitrifying bacteria.
from what i understand stress coat removes chlorine and chloramine but if used to excess something bad will happen, do know wat .
but i think it is ok for water changes.
I have cycled 2 tanks using Stress Coat as my dechlorimining agent with no problems. I have no evidence either way as to the effectiveness of the slime coat related benefits of this product. I would personaly not rely on it to have any significant impact on the stress levels of my fish (other than to create a chlorine/chloramine free environment). In my opinion a well cycled/mature tank that is well suited for its inhabitants is a much better stress reliever than anything you could add from a bottle.