Something eating corals

[MrKris]

Hey I've been trying to find out what has been eating my soft corals for the last few years. The following corals are the ones that I definitely lose if I put them in: pulsating xenias, zoanthids, blue/green star polyps, and clove polyps.

At first I had an aiptasia eating filefish nibble on my polyps the minute they were put down, but I removed him already. I have tried countless times to put in zoanthids to see what would eat them, but it usually happens when I'm not looking. I have a few suspects, but am not 100% sure they are the culprits.

The fish that possibly could pose a threat are: foxface, tang (highly doubt it), and a spiny sea urchin.

I have a few zoanthids growing in a corner that has some rock and rubble blocking it from direct access and they are growing fine between the nooks. I assume that if the foxface or the tangs wanted to they could get at them, but they seem to be untouched... This leads me to suspect the only thing that can't get at them and that is the spiny sea urchin.

The spiny sea urchin has been with me for at least 2-3 years and have been with me before I upgraded my tank. My previous tank was a lot smaller and the sea urchin was also a lot smaller, but the zoanthids were untouched but eventually eaten as well. The sea urchin is roughly the size of my fist (just the center of it without spikes - can attach photos if necessary). He has recently grown a lot larger and seems to keep on growing. He spends most of his time grazing on rocks...

I really want to avoid quarantining it because its large and very sharp. Does anyone have any experience with sea urchins eating soft corals? I had a tuxedo sea urchin that didn't bother the corals (except for carrying them around).

Any suggestions or experience would be greatly appreciated! Thanks

 

[miranda60]

you look best at night ... i suspect what eaten your zoanthus is Anseropoda placenta (small brittlestars)

 

[MrKris]

Mmmm... I don't think the small brittle stars are the ones eating my corals. I know I have a bloom of them but the only places I see them near is stuff that is close to dying. Additionally I have read other forums and spoke to other reefers which say they only target detritus.

 

[justthewife]

well...what else do you have in there as far as fish and stuff? The first thing that came to my mind was a possible nudibranch pest. Have you examined everything closely for them?

 

[MrKris]

Mmm I don't think there would be a nudibranch in there because they wouldn't selectively not eat the polyps and wait for them to repopulate. I think I'm going to quarantine the sea urchin and put in some polyps to see if it changes...

 

[justthewife]

Well...I did look around at a few places on the internet, mainly because I too have a sea urchin though he is very young. From what I have read, the urchins will eat softies if they are hungry (meaning not enough algae to sustain them). Some people suggested putting nori in every other day attached to a rock where the urchin hangs out to keep it happy and not eating your corals. I am going to keep an eye on mine.

 

[MrKris]

Welp... I narrowed down the list to 2 possible things... either the sea urchin or my foxface. I captured both of them one night and the day after I purchased some of the most "delicious" corals to put into the tank - must of been fate since it was soo bloody easy to catch both of them.

On a sad note... the foxface died when the sea urchin decided to masturbate in the tank and destroy the water quality - cloudy cloudy cloudy! The sea urchin looks like its gonna be dying too... quite sad since it was the size of a baseball.

On a bright note, I can finally have zoas and cloves and every other thing!

 

[wireefman]

foxface

 

[debadoo]

My urchin destroyed any coral it could reach. The only ones it left mainly alone were mushrooms. Every once in a while, though, it would take a bite out of those too. It was fed very well with nori strips every day. It totaly destroyed the skelital structure on my frog spawn so I would feed it cuttle bones like you get for pet birds. It still would not stop eating coral. I finally got tired of dealing with him so I gave him away. Since then I can keep just about any coral my lighting will allow. He was a really cool animal but I like my corals better.