I bought 6 for my sorority, I have seen 3-4 alive still, but I couldn't tell you if they weren't, just too many places for them to hide.
HAven't had any luck with algae wafers, I had five girls kicking up the sand to fight for it. Have some broccoli stem in there now, at least one stopped for a nosh, as well as the snails. Might need to learn to add some alternate foods.
My ghosties will eat poo of any kind (it's gross when you can see what they've eaten). Blood worms, brine shrimp, bits of decaying plant matter.