I'm willing to bet far more than 5-7 survived, its just that I can only find 5-7 pieces right now. we'll know in a couple more weeks to a month or two if I start having hundreds of mushrooms pop up everywhere, thats when the results will be known for sure, Right now this is still in the early recovery stage of the trial. I'm willing to bet if I had a 3'x2' rubbermaid tote with just live sand, light, and circulation it would be far easier to find all of the pieces and know how many were dying and surviving, it would be a purer form of the expiriment but all I had was my 12g tank so thats what I am doing it in.