Aaron,
This is in no way intended to be a Flame!!!
Also, food does play a very important part in the toxicity of certain animals . For instance, South American dart frogs, (the cool frogs that are yellow,blue, red, purple, green/black) are lethal to the touch in there native habitat. After living in captivity and feeding off of the makeshift diet of fruitflys, they do lose their venom.
This is by no way saying that what the lfs idiot told you was correct. I know this. This info was provided so if you ever came across another animal that interested you or for anyone, they will do the appropiate research necessary.