[fishfish]

Last week upon return from a business trip, I arrived to discover that a rock had blocked my main water pump which eventually created hypoxic conditions in the tank. All the fish (six) and my brittle star died. Luckily, the hermit crabs managed to sustain themselves as did some cerrith snails I didn't know I had.

Anyway, one week later, the legs of the Brittle star are still reeling around running food up and down themselves and reacting just as they did when the brittle star's body was attached.

Has anyone ever experienced this before and if so, how long will these legs keep living?

[BubbaWPB]

Some species of star fish are able to regenerate missing parts... a whole star fish can in some cases regenerate from a severed arm.

[showfish]

Sorry to hear about your loss. I have had Stars that have been almost cut in half, and regrow good as new. One of the many freaky things in nature. I wish you the best on your recovery.

[Penguin]

I once had a single brittlestar arm that the LFS threw in as a freebie. It didn't appear to have any part of the mouth attached to the arm, but I tried feeding it anyway to no avail. It lived for a couple weeks, but it eventually disappeared. I assume it starved.

If yours still has part of the central disk attached it may regrow.

[icemark]

There are no brains in a starfish, so if there is enough nervous system intact in a leg, it will re-grow the body.

[greenbean36191]

Brittle stars don't regenerate from just an arm. The legs might keep going for a few weeks but you might as well toss them.

[Ninong]

Originally Posted by BubbaWPB

Some species of star fish are able to regenerate missing parts... a whole star fish can in some cases regenerate from a severed arm.

fishfish is asking about a brittle star and as greenbean has already pointed out, brittle stars (phylum Echinodermata, class Ophiuroidea) cannot regenerate from just an arm. A detached arm in most species can regenerate the missing parts if it has at least a portion of the central disc still attached.

Sea stars of the genus Linckia (phylum Echinodermata, class Asteroidea) are an exception. They can regenerate a whole new sea star from just a piece of an arm.

Many species of sea stars can mutilate themselves (autotomy) abandoning an arm to the predator but saving life.

[optical]

i would like to see that-a starfish arm crawling around...

[Ninong]

I'm going to throw this in here for clarification purposes. The terms "brittle star," "serpent star," "starfish" and "sea star" are often used interchangeably in the hobby. This can be confusing. For instance, there is no taxonomic difference between a "brittle star" and a "serpent star."

It would be nice if people simply said Ophiuroids or Asteroids so that we would know which class they are talking about, but that's not going to happen in my lifetime, so I guess we're stuck with the confusion. Ophiuroids do not reproduce by arm fragments. The arm must have a portion of the central disc attached. Some Asteroids do reproduce by fragments of an arm. This is why chopping up the Crown of Thorns (Acanthaster plancii) to eradicate it doesn't work. They have to be manually collected and removed from the water. They do this in areas where its natural predator, the giant triton, has been eliminated.

Of course, all Echinoderms are dioecious (separate males and females) and reproduce sexually in nature but not in our aquaria.

[smidoid]

Ninong mate (sorry to be thick) but what's an Echinoderm? I.e. is a starfish one?

[Ninong]

Echinoderms are animals that belong to the Phylum Echinodermata. Examples would be sea stars (aka starfish), sea cucumbers, sea lilies, sea urchins and brittle stars.

You can read about echinoderms here, here and here.

[smidoid]

Marvellous. I'm off there now! Mind expanding stuff.

Wow! I love that reefkeeping magazine. I'll have to go read all the back issues now.

[Ninong]

Yes, it's a very nice free resource. We have recently started our own online reefkeeping magazine on this board. It's called Reef Hobbyist Online. You can check it out here.

[smidoid]

Originally Posted by Ninong

Yes, it's a very nice free resource. We have recently started our own online reefkeeping magazine on this board. It's called Reef Hobbyist Online. You can check it out here.

Wait... this is free? How? I guess I'll have to stick a hand in wallet (or the wife's ) and see what I can donate. I can't see any point in actually buying a paper one because not only is this just as good, it also saves trees!

Cheers!

Marc

[smidoid]

Originally Posted by Ninong

You can read about echinoderms here, here and here.

Yes, I'm in for it now (apologies to Douglas Adams for the misquote in the title...).

My wife is going to kill me now! I just spent a couple of happy hours reading and x-reffing those wonderful articles. Imagine - a starfish is effectively all brain - sounds like one of those wierd sci-fi B movies of the 1950s! Woh! Why am I in bother - it's nearly 3am that's why!!!

I even know what those little critters are that came with the last batch of LR - and why the poor beggars will probably die. It's certainly made me think HARD about keeping brittlestars - a "normal, everyday" starfish is totally out of it now; gone the same was a the fu-manchu lionfish: both sold at my LFS!

[smidoid]

...

[smidoid]

Oh boy. I wish I could put the missus into stasis. Every time I put the machine on she comes in and makes me jump so I do dumb things like double post. Bwahhaaa!