my serpent star just cruises the bottom of the tank and uses his little hair-tentacle things on his underside to sweep the food along his arms all the way to his mouth. it's pretty cool to watch. he knows when i drop in food, and he becomes active. he also eats anything that dies in the tank. my chocolate chip that i used to have (had to take him back to lfs when i got corals) would also cruise the bottom and eat food and detritus. i'd imagine you could feed them about any type of meaty food. mine weren't picky at all. and about the air thing, my choco chip was always half out of the water, so i really don't think there's a whole lot of truth to that.