Ctenophores run amuck!

[Anonymous]

Do these things reproduce by division? I have a Sarcophyton elegans (Fiji yellow) that had one when I got it. Now there are at least half a dozen, and they frequently perch on top during the day. At night they get all their feathers all tangled up in a big mess. The feathers drape all ofer the surrounding corals and extend to reach over half the tank. Not hurting anything, I guess.

If you don't know what a Ctenophore is, you probably have contacted them when swimming in the ocean. They are small jellyfish-like blobs that in the northeast are frequently about walnut-sized. There is a sessile version that generally perches on the trunk of sarcophytons at night and crawls up near the top during the night to extend long filter-feeding feathery extensions. If you have a wild-caught Sarcophyton chances are very good you have one- take a look at night.

 

[Anonymous]

How did you ID these as Ctenophora?

 

[Anonymous]

I plumbed my personal innate store or vague reef knowledge. Do you think they are something else?

 

[Anonymous]

To my knowledge, sessile Ctenophores are very rare and live very deep (and if I remember correctly, are limited to one species). There is also no sedentary/polyp stage (as in scyphomedusan and hydromedusan Cnidarians) in the development of Ctenophores, their cydippid larvae are basically miniature adults.

 

[John_Brandt]

Galleon,

What Dan is seeing is a very common but aberrent form of ctenophore. These are platyctene ctenophores of the genus Coeloplana. These are common on the surface of some soft corals and starfish as well as other bethic invertebrates.

There is a good photo in Sprung & Delbeek's Volume 2, on page 434. You easily see why the common name is comb jelly.

 

[Anonymous]

DOH! Yeah, I know of the Platyctenidans... I need to do some memory refreshing. The deep dwellers are a completely different order of ctenophore that live at the bottom of arctic fjords, I had recently read about them.

Actually John, Coeloplana has entirely lost the namesake ctene (comb) rows. So Dan, if it does have these, it is a different genus withint the Platyctenidian order.

Also, reproduction is sexual, but gametes are very likely to survive your filtration/pumps (we rely on the this hardiness to collect larval jellyfish and ctenophores from our culture systems). Development is very very fast in most ctenophores. Some species take no more than a day or so.

 

[John_Brandt]

Actually John, Coeloplana has entirely lost the namesake ctene (comb) rows. So Dan, if it does have these, it is a different genus withint the Platyctenidian order.

I may have gotten a little loose here with the comb image. These Coeloplanas have very long delicate feeding tentacles that are "combed", or as Dan says...look like feathers.

 

[Anonymous]

Ahh, gotcha.

 

[Anonymous]

Also, reproduction is sexual, but gametes are very likely to survive your filtration/pumps

Only sexual? Interesting. They found their way back to the same sarcophyton but not others in the tank... Do you think some species do not develop quickly and I may just have had small ones that were less evident, and there was no reproduction?

About the only thing I remember about Ctenophores from Marine Bio class is that they have colloblasts (sp?) or adhesive cells and not stinging cells like jellyfish. Also I think they are responsible for some of the cool, bioluminescence seen in the ocean sometimes...

 

[ReefRian]

Dan,

If they are the same things I had, the reproduce like mad but will eventually disappear. I had tons in my tank and now not a single one. I think they lasted about 4 months in my tank. They were really cool to look at and never bothered anything. Kinda miss them now.

Rian

 

[Anonymous]

When they reproduced did they stay on the same sarcophyton? Mine have feathery tentacles about a foot long, the body is an inch long at the most, just looks like a grey blob. Similar?

 

[ReefRian]

I never had a sarcophyton. I did have a sinulara. I'm not sure what they came on because I pretty much had them about a month after setting up my tank. They could have come on the LR or any of the corals I purchased or was given by fellow reefers. They first started in the same spot and then they were everywhere, even on the glass. They would always retract if I put my hand in and their bodies were really slimy if I remember correctly.

Rian

 

[Anonymous]

but they had the foot-long feathers?

 

[ReefRian]

yes. When they retracted or were released they were long strings and then they would open up and had very think strands all the way down. Like a fine comb or feather. Very fragile looking.

Rian

 

[Anonymous]

Dan, I think it is definitely possible that you had some develop over the course of time, and no reproduction took place. I think it is also just as possible that they have reproduced, who knows <shrug>.

The colloblasts will be on those feathery tentacles you see, and I can't see how they would have much a of a net negative effect on the coral.