Unknown critter, ID please?

[Jesse P.]

First off sorry for fuzzy pic. This critter was on the glass of my tank. Approximately an inch long, tannish brown color. Has two antenna and moves like an inch worm. I took it out of the tank because I didn't know what it was and would rather be safe than sorry. My concern is what it is in case I see more. I took a short video of it with my IPhone but it won't load onto the site . Thanks in advance for any help or advice!

 

[Michael Cronmiller]

Looks like Elysia, from the pic

 

[Michael Cronmiller]

A slug...got a couple but mine are bright green

 

[Jesse P.]

Elysia looks right to me after a quick Google search. When I took it out it flattened out in the bucket like some of the pics I found online. So are they good, bad or indifferent? Thanks again for the help everyone!

 

[KJ]

So are they good, bad or indifferent?

Elysia eats caulerpa., It depends on if you really like the caulerpa, if you have any because it is a main food source,that is why they call it Caulerpa Slug