M not sure if my serpent starfish is eating. I've had him for 2 weeks. He stays in the rocks. Always the same ones and only comes out partially,, a few of his tentacles when the moon lights are on or no lights at all. How do I feed him so I know he's being fed. Also in tank small box fish. Small fox face. Small cardinal. 4 hermits. 4 turbo snails. Please help with advice