How to control coral eating Nudibranchs

[iamwhatiam52]

I have had these in my tank for a few years but felt they had as much right to be there as anyone else. They are interesting little critters and I am President of the Don't Kill the Hitchhikers club.

They seem to live only on my Montipora caps, which grow like weeds. They were welcome to graze to their hearts content, lay their eggs, raise their families, and all was in harmony.

BUT..............................
These cute little guys are getting out of hand and doing some real damage.

Is there a natural predator or some way to control them? I don't want to wipe them out, just keep them from killing my corals.

Here are a few with eggs on the bottom of a 2 inch Monti frag.

 

[Sugar Magnolia]

Manual removal is pretty much the only option. Not sure why you want to keep some of them. Corals cost money.

 

[iamwhatiam52]

As I said my Montipora grows like a weed. I get to give lots of it away. Wanna buy some? Now that I think of it, what is the best way to make sure I don't pass the pests along to others besides manually scrubbing off the Nudibranchs and eggs?

Up until the last few weeks they have done no damage. Thus far they have cost me nothing and I just hate to declare war on these cool little grazers.

 

[Elysia]

Most people do not have a "live and let live" approach to coral eaters. I understand why, although I have attempted to keep a hitchhiking coral eating sea slug alive in its own tiny set up for a while -- I really like sea slugs. I'm glad that you take a similar approach; too many perfectly harmless hitchhikers are killed before they are even identified! (and I am not saying Magnolia does this, just have seen a number of ID threads where the requester eventually states that they disposed of the animal before a confirmed ID was ever posted)

If your "current tanks" is correct, could you put a piece like the one above into one of the 5 smaller tanks that is plumped into your joint sump and allow these critters to live on there, and take care to remove them from your main display? I would suspect that the ones that are hatching out and surviving are doing so by never being moved into the sump to begin with (although I could be wrong about that.) Are these slugs to be found in all six tanks?
It is unlikely that you will be successful removing all of them from your main display, anyway, if you have mature coral heads that can not be removed from the live rock. Perhaps the easiest thing to do would be to create a siphon using regular air line tubing and some rigid thin diameter tubing, and siphoning out all the adults and eggs that you can find. Often these animals are able to injest the stinging cells of the corals they feed on and use them for their own defense, thus few fish prey upon them.

 

[iamwhatiam52]

They show up anywhere I put a piece of Montipora. They may be on other corals too, but I have not seen them or any damage. Complete removal will not be possible because so much of the coral is grown into the tank and rock in places where it cannot be removed. Since I've only seen them on the bottom of corals when I prune, it will be hard to find them. I'm going to try using a mirror to find them, then siphon as you suggested with a curved tube. They do very little damage anyway, so a little siphon predation should keep them from getting out of hand.

 

[iamwhatiam52]

For corals or frags that I want to pass along, is there a medication to put in a separate treatment tank that will kill the nudis and eggs?

I have some beautiful pieces to trade, sell or give away, but do not want to pass along the tiny predators.

 

[sl-atl]

Check this out. The eggs are pretty much impossible to kill, so I'd suggest not selling/trading any frags until you decide how to dip them.

http://reefkeeping.com/issues/2007-09/eb/index.php

 

[iamwhatiam52]

WOW! What a long, complicated and not very encouraging article.

I would like to try the Potassium permanganate, but is it available is some form that will allow me to easily determine dosage?
The article mentions "It is also used in dilute solutions of 10mg/ml to remove freshwater snails and eggs from freshwater planted aquariums" which leads me to believe it may be sold as some commercial product in fish stores.

 

[sl-atl]

As far as I know you need to mix it yourself; all I could find pre-mixed was for ponds. I ordered some from a chemistry supply house but by the time it arrived it was too late... If you post to the Reef Chemistry forum some can help you.

You're likely going to have to remove your corals and dip them; from what I heard dosing the aquarium can kill fish and other critters that you want to keep around. IMHO these nudibranchs don't fall into that category!

Good luck.

 

[iamwhatiam52]

Yup, montipora will need to be removed for treatment. The article says that the medication kills fish and most other corals. Since my best montis are grown into the rock, medication will only be for the ones I want to give away.

I am putting a yellow cloris wrasse in the tank since some people have said they will eat the nudis. This may control them to a manageable level, but I hold little hope of eradicating them from my tank.

 

[mscarpena]

Melanarus wrasse are supposed to eat them as well. It will depend on the specific fish. Some fish will and some will not. G/L