It would be important to list or tell the potential buyer what that snake eats. Why would you even think of not disclosing that information? That's just plane bad business and bad ethics. Let a buyer know, what if they were buying the snake for their kid as a gift, the kid can't get the snake to ever eat and it dies. I would think it would make the kid think twice about getting another snake because (they are just to hard to keep alive) remember we are trying to help our reptile industry, and bad representation only hurts it no matter how small the cover up is.
Not implying you would cover it up just agreeing with you. I wouldn't want to have to post a gerbil-eater either.