I have had a tile star for about 3 weeks now. He hardly moves at all, and it looks like the tips of his arms are starting to decay(its colors are still bright). I was told this starfish is generally easier to keep than linkia stars, and I have had 2 linkias for months and they look amazing. Is it possible the tile star has a predator I'm unaware of? or did the LFS pull a fast one on me?