Inverts in my tank are used to being fed individually by baster. If you put your hand in and often just if a kid stands in front of the tank a stampede ensues of crabs, shrimp, starfish, goby. What I can't figure out is how on earth a starfish knows when I put in the baster. Smell of food in water? Sometimes they come tearing across the sand or out of the rock and grab onto the baster. Do they sense the food somehow or follow the other animals? I tested it once with an empty baster and several still came running. I think it may have had food residue inside, though. Or they just love me.