I don't remember buying you...

[Gindack]

Any clue what type of starfish this is? Was hard to get the camera to focus on it since it was so tiny.

[Dan H]

Asterina. They are very prolific.

[Gindack]

I have read mixed things about them online, should I leave it be or remove it?

[Reefgardner]

IMO I keep them because they are great little cleaners. Potential down side they do eat coraline algae, I had a completely covered purple rock and came home one day and looked like white footprints up the side. Sure enough at the top was an asterina. Coraline grew back fairly quickly.

[Sascha D.]

Asterina sp. is a tough topic to talk about. There's something like a hundred species of Asterinas, but only 5% are estimated to be predatory. The problem is that there isn't a definite way to tell them apart until you observe their behavior. If you see them on the glass or sand, then they're eating film algae and detrius. If you see them on corals then they're predatory.

One issue that causes debate is that most people say that Asterinas eat their zoas and it's a tough thing to prove. All known predatory Asterinas target LPS and SPS. That could be because many soft corals are noxious, but that's just a guess. It's more likely that the polyps were dead or dying from another cause and the clean-up crew was cleaning up. I wonder how many crabs or snails have been killed because they were eating something that was dead or dying anyway?

According to GARF, there are four types of coral eating Asterinas and they're all brown. Personally, I've had the whites ones for 14 years and never had any problems.