Pix & ID: Critters that come in your rocks: the good and the bad.

[garypalmer12]

Not sure what this thing is that's on my coral, it has loads of long tentacle things that spread across the sand

[cloak]

Terebellid worm?

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

[garypalmer12]

Not sure if this one is that, the worm things coming out are various thicknesses and colours, some are blood red while others are grey with dark rings

[cloak]

http://www.reefkeeping.com/issues/2002-06/rs/index.php

[brendanwp]

The white things wrapped around my sea fan I have seen somewhere but can't find it. The other thing looks like some sort of sea urchin. Thanks in advance!

20150130_071950.jpg

20150131_135045.jpg

[alexander_ktn]

The urchin could be a Colobocentrotus species, as for the white things: they do look a bit like some gastropod egg strnads to me, but it's hard to say from the image...

Cheers, Alex

[woodnaquanut]

I'm guessing yes because it doesn't look like any Bergia I've ever seen.

Can anyone ID?

[alexander_ktn]

It's an aeolid nudibranch - many of which are coral predators - so if you have zoanthids or montipora you should examine them.

[woodnaquanut]

Originally Posted by alexander_ktn

It's an aeolid nudibranch - many of which are coral predators - so if you have zoanthids or montipora you should examine them.

Thanks. Found it in a QT tank that has one zoa and one monti. Thought it was odd that it was half way across the tank from them. I though they would stay with their food source.

[alexander_ktn]

Most of the time they do, but some seem to stray a bit - maybe to find new victims... If it's a zoa-eating nudibranch you should see spiral-shaped egg masses on the colony.

[billy mitchell]

after the disappearance of hermit crabs and a turbo snail and my beautiful fire purple dart fish I stripped half the tank down looking for the culprit ...a big crab...after month of trying to catch it I finally have it in the sump ...now can anyone tell me what it is ...seems to have doubled in size in 6 months ...maybe might get to the dinner plate size .....[IMG][/IMG][IMG][/IMG]

[alexander_ktn]

Carpilius corallinus - the biggest crab of the Caribbean... Good that you have it in the sump. Feed it with meaty foods from time to time and it should make an interesting - albeit absolutely not fish or reef safe - animal.

It's edible & grows up to about 6 inches (carapace).

Edit: I have to add this image so one can appreciate the size it can grow to: http://www.n-the-florida-keys.com/im...orida-keys.jpg

[PsymonStark]

Hey - I need help to ID please.

Bought this Discosoma and i saw this weird sludge thing sitting inside the plastic bag.
there about 2-3 of them. Tried taking a photo - Pretty hard!

Flatworm?
Keep

http://i1167.photobucket.com/albums/...psb87f0811.jpg?

[Puffyluv]

Nope, discard...they aren't coral predators per se...but they hang out on mushrooms and block the light. :-( Too many and the mushroom can actually die.

[PsymonStark]

Originally Posted by Puffyluv

Nope, discard...they aren't coral predators per se...but they hang out on mushrooms and block the light. :-( Too many and the mushroom can actually die.

ah. ok. Thank you. Do you know what they called? Want to improve my knowledge

[Puffyluv]

Well, sort of...don't know the exact species that would be...but they are called acoel flatworms.

[cloak]

Originally Posted by PsymonStark

ah. ok. Thank you. Do you know what they called? Want to improve my knowledge

Maybe this link will help. There's a few pictures that looks similar.

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

[NaasReefer]

I have a few of these nudibranch going round my tank. Will they do any harm?

[alexander_ktn]

Originally Posted by NaasReefer

I have a few of these nudibranch going round my tank. Will they do any harm?

It appears to be an Elysia or Thuridilla species - algae eaters.

[xvgxcgh]

Thanks for those pix. Never have seen one of those guys. My cheato moss is so tame, in the pod department. But I have an amazing collection of limpets.

[woodnaquanut]

Originally Posted by alexander_ktn

Most of the time they do, but some seem to stray a bit - maybe to find new victims... If it's a zoa-eating nudibranch you should see spiral-shaped egg masses on the colony.

As a follow-up, I took some more pics. Does this look like eggs? Dead center in the pic and on the bump to the right of dead center.

[alexander_ktn]

Originally Posted by woodnaquanut

As a follow-up, I took some more pics. Does this look like eggs? Dead center in the pic and on the bump to the right of dead center.

I don't know what it is to be honest, but the zoa-eating nudibranch egg masses look more like this: http://s744.photobucket.com/user/jay...irls1.jpg.html
(not my photograph)

[woodnaquanut]

Originally Posted by alexander_ktn

I don't know what it is to be honest, but the zoa-eating nudibranch egg masses look more like this: http://s744.photobucket.com/user/jay...irls1.jpg.html
(not my photograph)

Thanks. Magnifying glass in hand, the hunt begins!

[nameless]

This is a strange animal that came in on my live rock. It seems like a sponge, but it reacts to movement, sucking in, closing it's siphons (one in the front bottom and on back, top). Isn't that odd behavior for a sponge?

(attached. Also, clearly, I need to go find some instructions on posting images in this forum)

[cloak]

Tunicate perhaps?

http://www.reefkeeping.com/issues/2005-03/rs/index.php