Can someone tell me what this is been moving around glass?

[patch60881]

 

[cloak]

Asterina star. Some people consider them to be harmless, I on the other hand don't trust them at all. Try using the search function at the top of the page. There should be all kinds of information regarding these stars here at RC.

 

[patch60881]

Thanks he just appeared

 

[Calappidae]

Asterina species. Most are harmless and reef safe however they can overpopulate and multiply in numbers.

 

[cloak]

The key word above is "most."

Until somebody can give me a definitive answer as to which ones are bad and which ones are good, I'll treat them all as bad.

http://reefkeeping.com/joomla/index.php/current-issue/article/45-reefkeeping-101-

http://www.coralpedia.com/index.php?module=Gallery2&g2_itemId=384