Is this starfish a coral eater

[robert serafino]

Some of my chalices montis are getting ate up looked at night did not see any pest. Then this morning this guy was on a chalice.

 

[Bribo12]

Looks like an asterina. I have a ton in my tank and no issue with corals being eaten. I’d say that’s not the problem but I’m sure people will comment who say they do eat coral. You could always try to remove them and see if that improves the coral health. If it does there’s your problem. If not something else is going on

 

[Duffer]

100% asterina starfish...as stated some have said they have seen them eat zoa;s while others claim harmless... I had a boat load of them and for me when it comes up a possiblity,i do not take chances and got rid of mine..

 

[reefandfish85]

what else you have in your tank? Peppermint shrimp are known to eat corals as well as other animals.

 

[robert serafino]

yes there are two peppermints.

 

[Mr. Mojo Rising]

Dark asterina is a possible pest. white ones are ok, but some species of dark asterina eat corals. Try to get an exact ID on that one

 

[reefandfish85]

yes there are two peppermints.

I bought peppermints to get rid of aiptasia which they did but they ate my baby hammer coral and cats paw , I saw them at night chewing on them. so I got all of them out ( I had 10 of them) except one he is too smart and can't catch him. Try to look at your tank at night when lights are out

 

[minus9]

Aquilonastra not asterina, unless you see it physically eating coral, then most likely it was doing its job and cleaning up. Peppermints can and will go after coral if they’re hungry (or just being peppermints). I would observe the nastra star and let it be. Are there any aggressive corals near the chalice?

 

[robert serafino]

No, Corals that are chewed on are in different parts of the tank. parameters are good. ph 8.1 temp 78 alk 8.06 cal 443 mag 1400 sal1.026. That is with the apex

 

[Foodfish]

I am no expert, but that looks more like a juvenile of a larger species to me, ive never seen a pic of a symmetrical 4 legged asternia

 

[Timfish]

It's an Aquilonastra spp. starfish and is a great scavenger. I see them with anywhere from 4 to 12 legs. The whole discusion around them seems to me excellent examples of misidentification, mistaken behaviour and assumed causality based just on heresay without looking at the research. Asterina spp starfish are preditary but only reproduce sexually and are shortlived so while it's possible some might get into a tank even if it did happen it's not going to be around long. Aquilonastra are one of the uncommon species that reproduce fissiparous or by splitting so are easy to identify by the different sized legs regrown after splitting. They perform an important function not only feeding off algae films but also feeding off microbial films including those on corals (at least ones that don't sting). FYI the mucus coating on corals ages and corals have to periodicely shed it to renew it and maintian healthy microbial processes (Ref 1, Ref 2). If Aquilonastra are feeding on zoas or softies I'll argue they are either benign or even beneficial as they may be reducing the unhealthy older mucus which can be full of unhealthy microbes which the animal is trying to get rid of and are far more likely to be the actual problem.

Here's an example, this Toadstool is doing one of it's periodic sheddings. The Aquilonastra have been in this system for years but only climb onto the Toadstool when it's shedding. In the first picture you can see the old mucus film, Aquilonastra starfish and areas they have cleaned off. The second picture shows the Toadstool a week later.