Not so beautiful hitch hikers, ideas?

[Heliox]

The first one showed up as small larva on the side of the tank the first few days and week of my set up. Now there are a few of these creatures on rocks near the bottom. Perhaps 1 cm in size. Am I right in assuming they are hydra, am I right?

The second picture reminded me of aptasia but I had aptasia previously, and these do not look the same, smaller and rounder. Any ideas?

The last picture was a long worm I found on the glass in the first few days I had the tank set up. I left it in the tank, hopefully it is not a pest, because I do not know where it has hidden. Was that a smart or poor decision?

I also found this worm swimming about the rocks. I think it may have been a bristle worm. Poor quality video, but anyone ever see bristle worms swimming in the tank?

[YOUTUBE]<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/4UeqbrYol3c&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/4UeqbrYol3c&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>[/YOUTUBE]

edited to add: the youtube embed looked like it worked in preview, now it is not showing.
Here is the link
YouTube - Hitch hiker video 1

 

[mantid]

First one looks like a small aptasia. The second pic is a button polyp. The last one I will leave to someone else.

 

[Heliox]

Thanks Mantid. Damn that it might be aptasia. And button polyp, thanks for the name, thought it was coral, but still learning and trying to retain names.

The worm in the bottom still picture was about 4" long, for anyone who might have an idea.

 

[seafansar]

Weird worm! But I agree with mantid on the first two.

 

[lcstorc]

First one doesn't look like aiptasia to me. More like a feather duster but not quite. Second one looks like a polyp of some sort and is likely fine. The last one I will be looking to see what others say. I've never seen one like it. Not sure I like the look of that mouth. Reminds me of a parasite of some sort that latches on but that is a flat out guess. The video is hard to see but it kind of looks like a bristle worm. I have never seen one swimming only in the rocks or sand so I am a bit puzzled there as well.

 

[seafansar]

That first one does kind of look like a feather duster, but I still think it's a bleached aiptasia. I've found some like that in my tank after turning over a rock: tiny and white. Can it totally retract into the rock (duster) or just into a blob (aiptasia. unless of course it has its foot in a hole. then it would disappear totally)?

Just watched the video. That's either a bristle worm (I've seen some swim like that, but only after brushing them off a rock. Never seen them let go of a rock and swim just for the heck of it.) OR this weird worm I saw in another person's tank once (sorry that wasn't very helpful). That worm would swim around like crazy at night and hide in the day time. Never figured out what it was, and I think a fish ate it or something since then.

 

[Boomer]

That video looks like an Epitoke, a reproductive stage of some Poly worms. I agree on the Feather Duster. The last one looks like one of the Nemertea worm.