ID help please

[sloshes]

Sorry, my wife has the camera right now. I was doing a flashlight check of my tank and spotted a strange critter. It was an inch and a half by one inch, most of it being a frill that wrapped around the entire body except the head. It had 2 feeler antennae working ahead of it and a long thin tendril behind. It moved slow like a nudibranche and seemed to flash a white line down it's back when I touched it. It's killing me not to be able to get a picture of this, I've been doing night checks for over a year with out seeing it. Any ideas where to start?

 

[sloshes]

This looks close but not quite. it must be a nudibranch. Can they be nocturnal?

 

[capncapo]

Sounds like it could possibly be a Dendroid nudibranch. I'm sure that some of them are nocturnal.

 

[sloshes]

I found it. It's a fleshy limpet, check it out
http://www.nudibranch.com.au/pages/8163a.htm

 

[mejiggery]

I have one too really cool algea eaters.

 

[sloshes]

Yep, that's it.