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Asterinas and Paly/Zoas


jservedio

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I constantly read all over that asterinas are killing peoples palys and zoas, yet I haven't experienced this with many different species of asterinas and dozens of types of palys and zoas over about a decade of keeping them and never saw any real proof that any actually do despite this longstanding belief. What I have seen them do constantly is consume dead/dying flesh off of zoas and palys and believe this is just being mistaken for them killing palys. Does anyone have any actual proof that an asterina starfish was harming and consuming perfectly healthy and growing palys and zoas?

 

I see pictures like this one all the time of Asterinas purportedly killing off people's healthy zoas and palys:

favia-paly-close.thumb.jpg.321f7173aa33131c234c4efd2cb8d138.jpg

 

But what it doesn't show, is the fact that the asterina isn't what harmed these palys and are in fact eating already dying paly flesh. Because if you zoom out a couple of inches, this is what you see:

favia-paly.thumb.jpg.51f06dd7386925ba48352095f12e3142.jpg

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IHaveADegreeInMarineBioBut

I don't have a picture, but I bought a zoa frag and there were new heads on it. I saw my asterina's on the new heads, but didn't think they were hurting them. The next day, the new heads were gone. 

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Well, I have the Asterinas, but I don't have zoas/palys in my current tank. I personally believe them to be opportunistic feeders who feed on weakened coral flesh when available. I've had three tanks since 2013, a 55 gallon, a 130 gallon, and a 13.5 Evo which is my current tank. Asterinas in all of them and zoas in the 55/130. Never saw them eat the zoas, but I also never had my zoas in a place to be stung or weakened as they were pretty far away from any other coral on an island.

 

However, I had a Rainbow Monti in my current tank that was light starved and the flesh in the shaded area and even small areas in the light I believe was eaten by an Asterina. I woke up to find right as the lights turned on, one slowly crawling away from a bare area at the base of the Monti that was covered in pale flesh and polyps the night before, the monti was on its way to death, I moved it into stronger light and it is coming back slowly, actually opening its polyps. I came out and observed the tank with the lights off multiple times in the middle of the night over the week after that and I never saw any crabs/snails/amphis, ect on the coral but I twice saw an Asterina under it before I moved it into stronger light. I checked and even dipped for MEN, but found nothing, and my other montis (flower petal, red monti Edit: all from the same source) were doing fine with no sign of tissue damage or MEN.

 

I have heard the species argument too, that we have multiple types asterinas and some eat zoas some don't.

 

All anecdotal obviously and could be something unrelated, but it's what I've experienced with these stars specifically.

 

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1 hour ago, IHaveADegreeInMarineBioBut said:

I don't have a picture, but I bought a zoa frag and there were new heads on it. I saw my asterina's on the new heads, but didn't think they were hurting them. The next day, the new heads were gone. 

How long did you have it and was it established in your tank?

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Some are bad and some are good. I have had them,destroyed about $300-400 worth of Zoa's. 

 

 Started with them being closed,then I slowly started seeing heads missing,then found a red one on my bowser's after he had moved 2 heads devoured,I popped the frag off and pulled him off. Couple days later more Zoa's disappeared off the plugs.. Come to find out I had about 5-6 crawling around the tank just munchin' on my lovely Zoa's needless to say,I ALWAYS dip. Even if I buy from well known shops or holes in the walls. 

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IHaveADegreeInMarineBioBut
2 hours ago, jservedio said:

How long did you have it and was it established in your tank?

They had been in the tank for a couple of days, but they've been open since the day I brought them home in February/March.

I mean there's a chance that those new heads were weak, but there were no signs of it otherwise.

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I keep the little buggers in all my tanks...I like them...cute and eat algae too.

 

In my experience...the white ones have only ever ate coral that was dying or damaged. If I had a frag stn..they would be all over the area that was dying back and so on but not in the healthy corals. I have zoas and palys and they grow just fine. I never see them on them or any coral really...unless it's on its way out.

 

Ofc..  injured zoas can recover or be saved...so they do expedite the process even if they didn't start it.

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14 hours ago, Reefkid88 said:

Some are bad and some are good. I have had them,destroyed about $300-400 worth of Zoa's. 

 

 Started with them being closed,then I slowly started seeing heads missing,then found a red one on my bowser's after he had moved 2 heads devoured,I popped the frag off and pulled him off. Couple days later more Zoa's disappeared off the plugs.. Come to find out I had about 5-6 crawling around the tank just munchin' on my lovely Zoa's needless to say,I ALWAYS dip. Even if I buy from well known shops or holes in the walls. 

I don't doubt at all that the asterinas actually ate the zoas, but I doubt they ate zoas that were perfectly healthy and thriving for one main reason: if the asterinas actually ate healthy zoas, their population would explode and they would simply mow clear through all of your zoas and there would be nothing left. Same as any other species on earth exploiting a favorable environment. How unhealthy a zoa needs to be before it gets eaten I have no idea, but asterinas are pretty opportunistic and nearly all species feed on bacteria (including the substrate they are on), diatoms, and some other types of algae.

 

I've read in reefkeeping that "only 5% of asterina species eat coral" but that is utter nonsense since there are only 15 species in the genus asterina. That said, there are absolutely coral eating starfish out there and there are dozens of stars that were originally misidentified as asterina and later moved to a different genus. I'd imagine it's pretty easy for a reefkeeper to see a little star and assume it is an asterina.

 

5 hours ago, Tamberav said:

I keep the little buggers in all my tanks...I like them...cute and eat algae too.

 

In my experience...the white ones have only ever ate coral that was dying or damaged. If I had a frag stn..they would be all over the area that was dying back and so on but not in the healthy corals. I have zoas and palys and they grow just fine. I never see them on them or any coral really...unless it's on its way out.

 

Ofc..  injured zoas can recover or be saved...so they do expedite the process even if they didn't start it.

That's pretty much exactly my take - they jump on any damaged or unhealthy flesh of any coral, not just zoas and palys.

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Seems to me that that was the case. They were the only pest I had in the tank. Also,it was a 2g cube,so the damage was done quick. Not only did I only have 1,I had 3-4 I believe. 

 

 I have had the pink,black,gray and red ones. They gray and black ones didn't seem to harm anything but they all got flushed regardless of the color. 

 

 Say 2g tank vs a 10g,the damage will definitely be catastrophic in a small tank. Riddle me not,everyone's experiences are diffent. Mine was bad. Have you had problems with them ? If so,your experience may not have been as bad as mine was. 

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