just got an urchin 2 days ago, and hes healthy (I think) full coloration, moves around, is sticking to the roof of his cave, no spine loss whatsoever. He just kinda sits in his cave and moves around inside, maybe moves almost out, but doesn't fully leave it. Is this normal tux urchin behavior? could he be having trouble figuring out how to leave it? Ive got some hikari algae wafers, should I spot feed?