Thank you so much for the help. This is the best I can get right now... they are at just they right angle I have to grab pictures through the length of the tank. I'll try to grab some better ones in a bit.
No response on any of the nems under the blue lights, or a UV flashlight.
That looks like a grey and not a snakelocks.
Now for the issue with Greys. They do reproduce fast, not plague fast, but fast.
Luckily they only reproduce by budding. No spores to worry about like aiptasia.
Easist way to remove is to place a piece of pipe over them and block flow. They will crawl up the pipe. When they do, you can remove them.
As much as I love all nems. Even have an aiptaisa and majano tank lol. They are harmless to most fish, but will seriously annoy corals.
If you plan to have corals, it is best to remove them. The great thing is, you could setup a species specific tank for them if you like them and it is super cheap and easy. A small 5 gallon petco special with an internal filter and a crap built in led is all they need. Add a little sand, couple of small rocks and top off the water every so often.
Being as they are a tidal species, they handle all temps and have no issue with some salinity swings.
They also can just be fed a little bit of mysis from time to time. Just do it directly in their tents and no waste.
Just as an example, I have had these warty sea nems in a tub with a crap job filter for a week with a couple of pieces of rock and they are doing great.
Tidal nems are the easiest to keep and the most forgiving.
Either way, if keep, awesome. If not, no worries. They will not work well in a reef tank, so just remember that.