whats this?

[Bobby]

Hi all,
About three weeks ago I saw one of these thing for the first time. I hope someone can tell me what it is and if their good or bad. I'am hoping its a good thing because now I found five. they seem to like to stay around my zoos but they do move around the tank.

[Reefland]

Hi Bobby,

I am not sure what that is exactly (great pic by the way) but my initial guess would be that it isn't harmful. Maybe Ninong or zhenya will catch this thread and have an idea.

[zhenya]

Looks like Aeolid Nudibranch to me and most of them are trouble if you have soft corals or zoanthids. All Nudibranchs are predatory and are very specialized at that, meaning that they will eat one particular prey. Have you noticed any zoa's polyps missing?
Here's an article for you to read about the Nudibranchs.
http://www.reefkeeping.com/issues/2002-09/rs/index.php

[CSeaSee]

Welcome to Reefland!
Whatever it is, it sure looks interesting. If you get an ID before one of us (and I don't have the foggiest!), be sure to let us know!

[Bobby]

Zhenya, Thanks for the help I think you got it. It looks like the one in the middle but the ones I have are brown and green. I haven't seen them really eating anything (key words haven't seen ). I guess none the fun starts,getting them out. What sould I do with them? Is there anything good about these thing sould I put them in the sump? I think this is a NO but i'll ask . They're kind of cool looking. Thanks for the help everyone.

[zhenya]

Hi Bobby,
I honestly think that you may be better off disposing of them. Some species of this Nudibranchs are known for eating pest anemone Aiptasia sp. but I don't think or know,really if the ones you have belong to this species. I would play safe in this case and try manually collecting them and euthanise them. They may live some egg sacks as well so be sure you check the areas where they hang out the most. If you move them to the sump, I think they will perish anyways if they don't have the food they need to survive there.