Monti Eating Nudibranchs and predatory starfish I 8/11/04
Dear Bob Anthony,
<cheers, my friend>
First and foremost I wanted to say thank you for everything you do. I believe it can truly be said that this phenomenal hobby has advanced so much over the years because of your dedication to it!
<thanks kindly... it is a labor of love>
I had a quick question if you don't mind, and also wanted to bring to your attention an interesting experience that occurred. I am of the opinion that everything in the wild has its purpose, and will not try to eradicate anything unless it is truly harmful.
<agreed... and yet, there is a joke somewhere in there about politicians. Well give lawyers a pass on this one>
I have a fairly large system with 8 plating Montis in it. I went on vacation and when I returned I noted two plating Montis were suffering severe tissue loss. I thought the issue was more water quality related, particularly since my calc reactor had been down for several weeks and the filter socks needed cleaning. Despite water changes and dosing with Kalk, the affected Montis continued to RTN. I had heard of these little predatory Nudibranchs, but did not think there was a chance I had them. I fragged one of the Montis, and what do ya know there they were. Tons of them (to be honest, even though I have an obvious degree of hatred for them, they are fascinating).
<Arghhh... you have not been diligent about quarantining your livestock my friend. 'Tis why you have this pest now. Do QT all things wet in the future - live food, live sand and rock, snails, corals, fishes, everything! <G>>
My problem is the effected colony encrusted hardcore onto a large piece of rock, there is no way I can pry it lose. I am suspect that these suckers are concentrated under the base. Is there anyway to rid of these things?
<they are very difficult indeed... do check the extensive threads on this topic at reef central. I cannot say the bad news any better than they have :p>
Is there anything in the wild that eats them?
<certainly.. but reef-safe? Hmmm... spec at this point. Some have said various wrasses and dragonets. None excel though reliably>
I do have one CBB, but I would think some form of reef "safe" wrasse would be better.
<perhaps... Tamarins or small yellow/green "Coris">
Also, wanted to mention in the past there was a dispute as to whether these little brown starfish we all have actually eat SPS (i.e. GARF).
<Asterina species... and yes, I have read the GARF info. I do not believe it is accurate.>
I had been in the SPS end of things and never had an issue so I was not concerned. Indeed they do eat SPS, the other colony I referred to above had tons of these brown starfish on the underside, right were the run line was on each plate. What is stranger, I have tons of across and non have been affected. Looks like it is time to buy a harlequin (there are plenty of these things to last the harlequin quite a long time).  As always thanks!!!!!!!!
<do check out my take on Asterina and other sea stars in the recent article on reefkeeping.com from a couple of months ago. Best regards, Anthony Calfo>

Monti Eating Nudibranchs and predatory starfish II 8/11/04
By the way, I am curious (from a scientific perspective) as to whether these predatory Nudi's show a preference for certain species of plating Monti, or whether this is just a random event.
<there are quite a few opisthobranchs that are obligate on one species of invertebrate or very limited (by genus usually) otherwise. There are lists of slug species and their prey available on the web. DO check out resources like the seaslug forum. We also have an extensive list of web sites and references on seaslugs in the bibliography of our book "Reef Invertebrates" by Calfo and Fenner 2003>
What I think is strange is the Nudi's have only affected one colony, none of the others have them (at least not yet). It would be neat to take frags of say 10 types of plating Monti, and see which species they show a statistically significant preference for
Thanks
<please do take photos and tell us of your findings if not write an article. Anthony>

Something eating SPS - Montipora
Anthony, happy holidays and hope all is well with you.
<Adam here today.  Anthony bumped this over to me since I just dealt with this problem in my own tank.>
I noticed one of my recent frags, a Montiporas Cap,  that is purple in color bleached around the edges about a quarter of an inch.  This is more then the  normal white tips from growth.  I attributed this to a drop in Alk while I was adjusting to my winter evaporation rate.  
<I did pretty much the same thing.  I attributed it to water quality, did some water changes and never really inspected the coral closely.>
However, I have noticed a small white spiral looking thing on the white part of the coral.  Looks almost like a very small white fan worm (at least the ends of the fan worm anyway).
<The critter you saw is an Aeolid Nudibranch.  They seem to becoming quite common in the hobby, likely from frag trading.  They seem to favor plating Montiporas, but will move on to branching forms.>
I also noticed a small white area on my
established, thriving purple cap.  Could this be a bug or something?  Any ideas or am I  just seeing things.
<The white spots are where the Nudi's have eaten the coenosteum (tissue between polyps) of the coral.  Unfortunately these are very real and quite difficult to get rid of.  Manual removal is the only way to do so without significant risk of killing the coral.  You will have to remove the infested corals every day or couple of days and pick or scrub off any Nudibranchs or eggs.  It may be best to this in a bucket of tank water since the critters tend to collapse under their own weight and become difficult to spot out of the water.  After you are 100% sure you have eliminated them, continue to check your Montiporas at least weekly.  I continued to find one or two a week for about a month.>
Thanks
<No Sweat, and best of luck!  Adam>
Andrew

Montipora Eating Nudibranch Predator? - 05/26/06
Hello WWM staff,
<<Hello Stephen>
I recently noticed a small number (at least what I could see) of Nudibranchs consuming various species of my Montipora.
<<Mmm, very bad...and their numbers are higher than you realize>>
This was very disappointing as I have gone through a QT for everything, but obviously something slipped by my inspection.
<<Indeed>>
Over the past 3 weeks I have moved most of my Montipora to a frag tank where I inspect and manually remove the adults and eggs at least every other day.
<<Prolific breeders, I would do this daily...if you're serious about eradicating the Nudibranchs>>
Finding very few now and found none yesterday!
<<Keep checking...a few weeks quarantine in order here>>
I do however have 2 large colonies of M. digitata that I can not remove completely as they have encrusted large rocks at their bases.
<<Different species about (Nudibranchs), but my experience with these critters is they showed a definite preference for the plating (e.g. - M. capricornis) and encrusting (e.g. - M. danae) Montipora over the branching varieties>>
Just yesterday I noticed 1 Nudi at the base of one of these colonies (Where there is one, I'm sure there are more).
<<Yes>>
After dispatching this Nudi I inspected as best I
could and can not see any more.
<<Again, in my experience, once the food source is removed they tend to "disappear" quickly>>
So having found this in my display still and not being able to easily remove all of the Montipora, is there a fish predator for these guys that would make an appropriate addition to a community reef tank for a 90gal?
<<Not that I'm aware...for sure.  Some of the reef-safe wrasses "may" eat the Nudibranchs, but I have never witnessed/heard confirmed reports of this.  If you wish to try, a wrasse from the genus Halichoeres might be a good choice>>
I have seen a couple of species or wrasses mention, but little direct discussion.
<<Indeed...I once experienced and episode with these Nudibranchs...I had wrasses from four different genera in my tank (including Halichoeres) but could never discern any of them feeding on the Nudibranchs>>
Thank you,
Stephen
<<Quite welcome, EricR>>