Anyone know what this is?

[DaJMasta]

Was it floating, or was it alive in the tank?

It could be something like a sea cucumber, but it really just looks like a caterpillar fell in your tank.

 

[Palmtree14]

Was it floating, or was it alive in the tank?

It could be something like a sea cucumber, but it really just looks like a caterpillar fell in your tank.

There was 2 of them on a mesh bag submerged in my refugium. When I took them out, they were crawling around on my hood.

 

[DaJMasta]

Well I don't know if this is still current, but checking to see if they float (not a cuke) or if they can wander around out of water/not wet (not a cuke) would tell you.

Most of the spiky looking red cucumbers I can spot have more spikes, and there is something very caterpillar-leg-like the flesh that meets the base of the spikes looks like to me. That said, I don't see an obvious candidate for what caterpillar it would be either. Appears too bloated for any bristleworm I've seen, they'll also usually only have legs on either side in a plane through the center, whereas caterpillars will have a bottom side with the legs and a top side without.

 

[Reefer Reboot]

When I took the pic it was out of water.

That explains the difficulty in IDing this. Bristle worms will look "spikey" like a sea cucumber when out of the water and the bristles are all clump together. Can you take another picture with it under water with white lights on? How long is this?

 

[Palmtree14]

That explains the difficulty in IDing this. Bristle worms will look "spikey" like a sea cucumber when out of the water and the bristles are all clump together. Can you take another picture with it under water with white lights on? How long is this?

I removed them because I couldnt tell what they were. If i see another one tonight I will snap a pic submerged.