Friend or foe

[ibefishy]

Anyone have an idea about this thing? Is it a nudibranch or slug or what? I have checked websites to try and ID it but it is kind of hard to go through and look at all the photos. I was hoping some of you may of seen one or had one in their tank. It has been hanging out by some zoas but has since traveled on.

Thanks

[ibefishy]

Upon further inspection I have now found two of these in the tank and both have been removed for the time being.

[Ninong]

Short answer: foe.

It's an Aeolid nudibranch. Probably one of the ones that eats Zoanthids.

You should remove and discard any that you see as soon as you see them.

[ibefishy]

Thanks Ninong, Thats kind of what I thought so I pulled them out and now will keep a watchfull eye for any more. Being that I found two there may be more, is there anything that eats those if they become a problem?

[Ninong]

...is there anything that eats those?

Not that I know of. You should make a special effort to remove them as soon as you see any.

[ibefishy]

An update to my original post. Last night I found about ten of these little nudibranchs on one of my zoa colonies. As it happens it was one of the ones I got from the the frag swap I attended last month. No sign of them on any of the other zoas in my tank. Now these ones are very small, I know I cant get them with fingers, but my long tweezers should be able to pluck them off, but is there any other way to eradicate them when they are so small and hard to see? Would a dip in something help. I remember seeing things about freshwater dips and was wondering if that might help? Is there any kind of medication(not that I want to go that route) that could help? I have a quarentine tank set up so I am ready for whatever needs to be done.

[Ninong]

Aeolids in Aquaria

With only a couple of exceptions, aeolids should not be welcomed with open arms by aquarists. They all eat cnidarians, and many of them are specialized to eat some species of the decorative livestock that aquarists keep. Numerous species have found their way into aquaria from time to time. Generally, the solution to maintaining these animals is simply to remove them. Solitary hitchhikers are seldom able to set up or maintain a breeding population. However, there are some exceptions. Some, typically small, species can pass through their entire life cycle in a reef tank. These particular nudibranchs pass through most or the entire larval period within the egg mass, and do not need to feed in the plankton. Consequently, they can proliferate in an aquarium. As these nudibranchs are specialized in diet, they have picked up the common names of "Montipora-eating nudibranch" or "zoanthid-eating nudibranch." It is likely that there are several species in each group, and controlling them is difficult. Being aeolids, few animals will eat them, and being small and mobile they can spread throughout a tank and infest it before being noticed. Among their few predators are some other slugs (see here for some movies of them being eaten; note how well the cerata repel the potential predator, Pleurobranchaea, and are ineffective against the other, Navanax). Interestingly enough, these other slugs lack eyes, so any aposematic coloration is "wasted" on them. Dips of various sorts may be used to control them in aquaria, but these vary in efficacy. As the converse of these problem aeolids are several other small species, all sold under the "umbrella" name of "Berghia." These nudibranchs are bred and sold specifically to prey upon the pest anemone species in the genus Aiptasia. Large aeolids are often strikingly beautiful animals, but they are not reef aquarium safe. Smaller aeolids tend not to be as highly colored, and some of them are useful in aquaria, but the majority of these are also not animals most hobbyists would want to try to maintain in their aquaria. As with numerous other highly colored marine animals, one might wish to recall the aphorism that "Beauty is in the eye of the beholder."

Suggested reading on how to eradicate them: here.

Good luck!

[ibefishy]

Thanks a ton Ninong thats is the kind of info I was looking for. I did a search but didnt come up with that. Once again thanks.

Nate