So do Asterina stars eat corals?

[fasteddie99]

The first reason I ask is because I have a green brain frag that looks like its been chewed on in 3 spots. Each spot is about 3/16" and its been gnawed on (presumably) right down to the skeleton. Each spot appeared about a month apart and I saw an Asterina star in the same area every time I noticed the "spot".

The second reason is that I have a staghorn hermit crab which basicaly has a coral on his back for a shell. I think it is formed of hydroids if I'm not mistaken. Well 2 weeks ago I noticed that he wasnt moving anywhere in the tank. He literaly sat in one spot for 2 days and just cleaned his antenae. After realizing there was something wrong with him I started feeding him a big chunk of thawed scallop and he ate franticaly. I target fed him every day until he finaly over came whatever was wrong with him, now hes doing much better. Why did I tell you this? Well when he got sick, I was looking at him with a magnifying lens and I noticed a bare patch on his shell. It literaly looked like a lawn mower went down the side of his shell. It is starting to fill back in now as he gets better, but I wonder if something, possibly an Asterina snail was munching on it?

I may be totaly off by thinking these so called herbivores are eating my brain and crab, but I still wonder So I have been picking them out of the tank every time I see one. So far I found 4.

Here is a pic of the staghorn hermit. He is awsome to watch.

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[impur]

Thats one cool crab!

I can't say for certain about asternias, but i find them wrapped around zoa polyps all the time. So i remove them if i find one.

 

[ct_vol]

That is a cool crab... :thumbsup:

I venture to guess that the Asterina debate is similar to that of the Amphipod debate... Most people see them on dead or dying portions of coral, so are they feeding on the decaying portion damaged by something else, or are they themselves inflicting the damage???

I personally believe that there are many types of Asterinas and amphipods out there, some of which are carnivorous and others which are herbivores/detrivores... I have a Harlequin shrimp that keeps my asterinas in check, because I flat out don't trust them... That and it can be annoying having them all over your glass...

 

[cabanaboy1218]

I like that crab every time I am down at the LFS I always debate getting one or two how are they in the tank? Active? Destructive?

 

[gooyferret]

That is awesome!

 

[GrimReefer82]

Asterina stars are completely reef safe. They only eat decaying parts of the corals. They are beneficial because they can stop necrosis on some corals. I have bristle worms, asterina stars, collinista snails and amphipods and they are all great. I see the asterina stars all over my glass, their main diet is algae. In nature corals have dieback just like any other organism so wouldn't you think these occurences are normal in our systems?

 

[fasteddie99]

<a href=showthread.php?s=&postid=15332198#post15332198 target=_blank>Originally posted</a> by impur
Thats one cool crab!

I can't say for certain about asternias, but i find them wrapped around zoa polyps all the time. So i remove them if i find one.

Thanks.
Yeah I just removed my 5th one a little while ago.

 

[fasteddie99]

<a href=showthread.php?s=&postid=15332853#post15332853 target=_blank>Originally posted</a> by cabanaboy1218
I like that crab every time I am down at the LFS I always debate getting one or two how are they in the tank? Active? Destructive?

He is very active. He pretty much stays on the sandbed and picks pebbles up with his small claw, cleans each piece off and spits it out. The other claw is huge and he uses it as his door. It is a perfect fit and seals perfectly on the shell. So when it gets scared his whole body retracts into the shell and he shuts the door with the jumbo claw.

So far he hasnt been destructive. I feed heavily so I think as long as he is fat and happy he should stay off. Only time will tell though. I've only had him for about a month.

 

[fasteddie99]

<a href=showthread.php?s=&postid=15332991#post15332991 target=_blank>Originally posted</a> by GrimReefer82
Asterina stars are completely reef safe. They only eat decaying parts of the corals. They are beneficial because they can stop necrosis on some corals. I have bristle worms, asterina stars, collinista snails and amphipods and they are all great. I see the asterina stars all over my glass, their main diet is algae. In nature corals have dieback just like any other organism so wouldn't you think these occurences are normal in our systems?

Cant argue with you there. Might be a coincidence that they just happen to be in the area, but they arent very nice looking anyhow so I dont mind not taking any chances with them.

 

[greenbean36191]

There are LOTS of species of Asterina. Some of the larger species are known to be coral predators. It's very likely that at least of the few small, cryptic species are predators as well, but they're impossible to tell apart without genetic testing so that makes it hard to study their diets. However, not all species seem to be corallivores. I've done feeding trials with some I collected and even after months of starvation the stars in the coral group would not feed on healthy or dying corals.