Hydroid identification... no graphic  - 2/15/2006
Hey pros got a quick question for you.  I was browsing through your array of posts and articles when I stumbled upon the "Hydrozoan" section.  I looked
through the photos and found one that is similar to something I have in my tank.  The picture I'm referring to is under a post entitled "Bad boyz
hydroids- 12-30-03.  The picture shows small tube-like structures protruding from the live rock with tiny little white heads.
<Covers many species...>
I have something similar in my aquarium.  There are several small (1/16 to 1/8 on an inch) solid tubes, purple in color (covered in coralline algae) that appear to be growing
out form the coralline algae (or maybe the coralline is just growing onto it). On the end is a tiny filamentous structure (looks like a clear bubble but
it's very small so hard to tell) but in either case it looks as if it could pull inside the tude.
<? Not retractable>
These little tubes have been there for at least a few months if not year, I never paid attention to them, and I have never noticed
them bother anything.  There are no corals growing near them, but I assuming if I see them in that spot then they are probably growing other places too.
All corals (Shrooms, xenias, colt, zoos, and gorgonians) seem to be doing fine.  Can I do a test by placing a small xenia, perhaps, near
this "hydroid" to see what happens?  Are these little tubes always "bad" or can they be beneficial/neutral creatures as well?
<As long as "stay small", to themselves>
  I have seen other similar creatures that live in tubes (some straight some coiled) that have feather duster like heads.  I'm certain these aren't harmful, but how do
you visually separate these from hydroids?  
<If trouble, best to remove, denude from the rock>
One post stated that they can look like corals, algae, or jellyfish.  That describes many small creatures I see in my aquarium, how do I separate the good from the bad?
Thank you
Jon
<... a photo or drawing please. Bob Fenner>

Sea fan approximation 02/12/06
WWM Crew,
<<Arnold>>
I am requesting your assistance in identifying a particular type of coral I have acquired.  It is yellow in color, resembles a dead tree in shape, and has white polyps protruding out from the entirety of the structure.  Any help you could provide would be greatly appreciated.  Thank you for your time.
Sincerely,
Arnold
<<No way to say without a sharp close-up photo.  But I'm going to venture a guess here and say you have a non-photosynthetic gorgonian...will likely starve to death within months.  You really should research your livestock BEFORE you acquire it my friend.  Regards, EricR >>

Mushrooms invertebrate or soft corals?   2/9/06
I have seen many forums sectionalized mushrooms as soft corals.
however, I am incline to believe they are closer in invertebrates.
what is confusing is not clear cut.
<... Mushrooms (Order Corallimorpharia) are not Soft Corals (Order Alcyonacea)... many stinging-celled animals (and even some non-cnidarians!) are termed "corals" by hobbyists and lay people. Much of their higher taxonomy here: http://wetwebmedia.com/cnidaria.htm
Bob Fenner>

Jellyfish??   1/27/06
Hi.  I have a 45 gallon reef tank with about 60-70 lbs of live rock and live sand.   My tank is in great condition just turning 1 year. :)    I currently have hammer coral, waving xenia (SP?), cabbage coral, candy, mushrooms (diff varieties) brain coral, assorted polyps, and a another coral soft yellow and i cant for the life of me remember the name.   The tank only has 2  clown fish, 2 engineer gobies, 1 black and yellow clown fish (gift from gf... She doesn't know name)  1 tiger pistol shrimp,  1 arrow head crab,  1 fire shrimp,  1 sally light foot (think that's name)   I have a not so standard setup as far as filtration goes.   I converted my sump into a fast water refugium.   In there I have 4 inches of coarse live sand, live rock and assorted live plants and kelp,  A hitchhiker anemone white in color don't know what it is, and a family of copepods all happy and growing.   I have Eheim filter filled with bio balls, and finally I set up a 10gallon tank as a slow water refugium.   the slow water refugium gets water thru 1 air hose via gravity and gets returned to sump via gravity.  The slow water refugium has a large number of copepods and other "buggers"  I don't clean them and pretty much let them be.   Now after all that rambling,  recently only in my slow water refugium I have a large growth of ... only what I can describe as small anemones  they are white and about 1/4 inch long.  The are attached to the glass via a small tube not hard very short 1/16th inch then a disc with tentacles very fine and numerous.   The can sway and retract if disturbed.  there are a lot of them but I leave them be since that is what I put the refugium in for.   But after a while the head of the anemones starts to change turns discus in shape.  then it starts to pulsate,  then it breaks off and what looks like a jelly fish ... kinda like a small slightly opaque mushroom,  swims around.   they are multiplying the swimming parts seem to disappear after a while.   Any Idea as to what this can be?    I can try a picture if that will help more :)   
<Likely are some sort of scyphozoan, Hydrozoan... Just as likely to cycle out. Bob Fenner>
Thank you
Javier Fernandez