Need help ID'ing this critter in my reugium...

Justin....#JAMAS · Mar 6, 2018

OK I just set up this sump last week and have just started to put phytoplankton to help with the corals...I added chaeto last week and its doing well, but I looked today and saw this guy moving like a slug on the glass with a long skinny body, lookalike 4 legs, 2 on each side, and a head with two white tentacles coming out! Weird! The guy told me the chaeto they got in was clean chaeto, but they will tell you anything! The first thing I thought was a nudibranch? Maybe? But need help please! And advice on what to do? Get it out let it stay? Lol thanks everyone! I tried uploading a short video, but it wouldn't let me! So here is a couple pics!
Also, before I knew what a sponge was I tried suctioning one out and some of it got in the current and I'm not sure if its that or a new rock that I added, that I now took out, but there is like a white film algae stuff that seems to spread and get all over rock and sponges seem to be popping up everywhere! The white film, doesn't hurt any corals or anything so far, but it just isn't the best sight and was wondering if anyone knew what that is?? I tried to get the best pics for both of my issues! Cheers!

Now thus white filmy wavy stuff is on the dark rock right in the middle and on the right side but hard to see...thus stuff seems like it gets everywhere!

Here, its on the bottom left corner of this rock....

TheAquarian · Mar 6, 2018

Top two photos are definitely a Nudibrach, I cant tell from the photo but it doesn’t look like a bad one to me I would leave it in the sump and watch it. It could be a good thing. As for your sponge problem again I can’t really tell from the photos if it is a sponge it’s good for your tank.

Justin....#JAMAS · Mar 6, 2018

Yeah it looks like a nudibranch!! He mist have came in on the chaeto!? Yeah I cannot keep him in there, good or bad, I don't want to take that chance, and if he lays eggs!!! Oh no lol
And there are sponges popping up everywhere but I feed only one time a day and only about 1 minute what the fish eat only! So I'm not sure where this white film came from other than a new rock I put in!

Justin....#JAMAS · Mar 6, 2018

Thanks for the input man! Any other batters?

KJ · Mar 6, 2018

Nudibranch.
https://www.google.com/search?q=zoa...X&ved=0ahUKEwihteat4dbNAhXE7oMKHaZNCdkQsAQIGw

KJ · Mar 6, 2018

Bryozoan? https://www.google.com/search?q=bry...ved=0ahUKEwja08nC4uHNAhVJ2GMKHbVhDoAQ_AUIBigB

Justin....#JAMAS · Mar 7, 2018

KJ said:
Bryozoan? https://www.google.com/search?q=bry...ved=0ahUKEwja08nC4uHNAhVJ2GMKHbVhDoAQ_AUIBigB

Yeah I think I have some of these growing, maybe not, they are hair like things growing in places! But the stuff in my tank is white like a sponge but looks like a thick patch of hair algae but white!

TheAquarian · Mar 7, 2018

I think we’re going to need a better photo. You could look here https://www.lionfishlair.com/hitchhikers-guide/ see if there’s a photo that looks like what you have.

Justin....#JAMAS · Mar 7, 2018

TheAquarian said:
I think we’re going to need a better photo. You could look here https://www.lionfishlair.com/hitchhikers-guide/ see if there’s a photo that looks like what you have.

Yes I think it was a nudibranch! I'm glad I caught it! I doubt it could of got up in my DT but you never know! I took out my sump and pretty much cleaned it out, and the nudibranch was in the chaeto! Tough little guy to get out but finally got him last night! I went to my LFS today, and asked them where did they get their chaeto from, BC its full of nudibranch's and its got little sea shells in it everywhere and other things I picked out! Don't most vendors who sell chaeto aquaculture it, to make sure its very clean? It seems like this chaeto, someone just bent down and grabbed a glob of it straight out of the ocean, full of pests! Anyways, got everything and anything that could be harmful out and got my sump going! Thanks for the quick responses! Probably going to do a study and post on chaeto and hitchhikers associated with it!