Slug?

Saw this thing for the first time today. I have purchased no live rock only coral frags and have a couple different types of snails in the tank. I have been noticing small white dots with a dark center on the glass and rocks recently and assumed they were snail eggs. Sorry for the blurry pic, not a whole lot to see, it’s about ¾” long.
Thanks,
John

 

do you guys think it could some kind of nudibranch? it kinda looks like one

 

It's probably a nudibranch. The lighting has washed out any detail, so I can't be terribly confident giving you an ID. It doesn't appear to have an external gill on the dorsum unless it's retracted, which is possible. I'll assume it doesn't have one, and tell you what I think it isn't first. It could be a pale Plakobranchus ocellatus. They come in several shades, from grey to brown mottled to almost white. If it's this species, it's no problem in your tank:

The Sea Slug Forum - Plakobranchus ocellatus

Again assuming it doesn't have an external gill (looks like feathers on its back), I'll guess it's an arminid nudibranch. Some of them eat clove polyps and other polyps, and they're generally bad news. I didn't see a pic of a totally white one on my quick run through on the net, but pics of totally white ones have been posted on some of the other forums. You can check this species for a general comparison, and then scroll through the Armina and Dermatobranchus species on the Sea Slug Forum to see if you see a better match:

The Sea Slug Forum - Dermatobranchus albus
The Sea Slug Forum - Species List

If it doesn't look like a Plakobranchus, it's probably something you don't want in the tank with your corals.

Cheers,




Don

 

if you don't have any rock, then it must have come in on the coral. and if it came in on the coral, then that's probably its food source. I learned the hard way and the nudibranch I had eat my zoas. I got rid of the nudi after 2 weeks and when my zoas opened I could see the bite chunks out of the zoa. I say get rid of it.

 

Thanks for the in depth answer and the links guys! You’re correct it has no external gills and of the coral frags I’ve gotten the Clove would have been the easiest to hide in. I think he’s a goner when I see him next even though I have seen no damage to any of my corals.

Thanks again for the help!

John

 

I usually put my coral frags in a bowl with some salt water and shake it a little. You wouldnt believe the things that come out of the rock and coral and into the bowl. Yesterday I found this bright orange worm come out of my GSP rock before i put it in my tank. A starfish also came off the rock, along with some brine shrimp and copepods. Not that those are bad, but Im glad i got that orange worm.