Supposedly the Blue Linkias are difficult. I've had an orange star (not a Linkia) in my tank since January when I first set it up. He's very active - cruises all over the tank. I recently picked up a Purple Linkia a few weeks ago and he's doing great. Here's a good link to some starfish reading...
I had a blue one for 1 1/2 years and he's lost a couple of legs and grown new ones. now I have at least three. weird way to reproduce. I like our way much better.