New Hitchikers ID please

[jabberjaw]

Hey everybody,
have had my tank going for over 7months now and thought that I had already seen all of the 'surprises' my live rock had in store for me (snails, bristle worms, mini corals, etc) then over the last couple weeks these guys have popped up out of nowhere!
Im pretty sure the first one is some kind of brittle star, then second one I've no idea about, and the third im guessing is type of sea urchin.. and unfortunately I believe the last one is aptasia (d'oh!)

Any ideas??

[Reefscape]

1) A brittle star..

2) Looks like a nudibranch to me, could do with a close up photo..

3) Urchin - possibly echinometra viridis..

4) Aiptasia..

[jabberjaw]

thanks reefscape, the second one isnt a nudibranch as it is kind of round'sih and has hard shell on it (with a bit of coraline too!)
Hope this pic is of more help (I'll try and get a few more when he comes out again)

[Reefscape]

If it moves, its either a nudi or a seaslug, with them colours...

[jabberjaw]

even with a hard shell?

[Reefscape]

If your certain it has a shell, all be it a reduced shell i would guess, then seaslug i would suggest..

[jabberjaw]

well the need to know got the better of me so conducted a seach in the tank and found him... this should make it a lot clearer (the first image is a bit deceiving, the shell is actually relatively flat and not a cone shape like the image kind of makes it appear)

[Reefscape]

Ahhhhh.....LMAO...i was looking at the pink as the body, as arrowed here....

[Reefscape]

Star snail me thinks...have a peruse over these...

http://www.eurasiashells.net/fam_turbinidae.html

[jabberjaw]

lol
yeah, I thought the purple bit was the creature too when I first saw it :)

thanks, well I guess that solves that little mystery... well, until the next one comes along :D

[Reefscape]

Glad we nailed it mate....

[jackiomy]

How fun! Bonus!