Lettuce sponge with feathers?
Hi Bob!
<Hello there>
I have searched and searched through this web site but could not find anything similar to this problem...
I have had an orange lettuce sponge in my reef tank for about 3 months now. It has been doing fine, but a few weeks after I got it, I started noticing a red feathery type of growth on it. The "feathers" continue to spread and grow larger, and I have no idea what
this is. Is it a type of harmful algae, or just a natural part of this sponge? A turbo snail wandered onto it once and ate most of it off, but it
just grew back. Any ideas?
<Likely some type of hydroid. See here: http://www.wetwebmedia.com/cnidaria.htm 
I might leave all alone... but am inclined to mention that if your sponge seems to be suffering from this growth, I might "snip" it off... with sharp scissors... with part of the sponge where it's attached... and siphon/vacuum out as much of the material as you can after. Bob Fenner>
Thank you,
Laura

Unidentified Critters... stranded hydroids 6/9/04
I have had a 30 gal reef tank for about a month now.  I have 45 pounds of live rock and 3 corals so far.  Also some snails, hermit crabs, a sand star and a blood shrimp.  No fish yet. I have been diligently checking chemical balances and everything seems on target.  In the past few days I've noticed some unusual critters appearing on the glass and live rock.  I've seen several very small snails (1/32 inch) which began appearing before I introduced snails into the tank, so I assume they've come from the LR.
<yes... indeed> In the past week I've noticed several translucent
critters on the glass which move like snails, have no shells, are about 1/8 inch long and have 2 points at their back end.
<sounds like a flatworm... the little milky white ones prey on copepods. All are harmless>
From reviewing other questions responses you've given, I've identified them as flat worms which are not harmful.  
<Ah, BINGO- you win the hairy kewpie doll! Very glad to hear you in the archives :) >
However yesterday I've noticed a new critter which, in reviewing your Q&A's, I cannot identify.  These seem to have emerged within the past day.  They appear to be long white strands with a single row of "hair" (1/16-1/8 inches long) on one side. (Almost like a 1 sided long skinny white feather.)  
<Yikes... I recognize it already. It is a very distinct description. Your creature is a fiercely stinging hydroid. Do remove it... it will sting you and your animals alike>
They seem to be about 2-4 inches long and appear to emerge from a jelly like polyp on the rock. They drift with the current from my power-head, and periodically retract back into the polyp.  I assume that they are "netting" micro-organisms, then "reeling them in" to be consumed. These strands are so thin that they
are not visible unless you are very close to the glass.  Any idea what these things are?  Are they dangerous to the other life in the tank?
<yes... do be careful. Best of luck, Anthony>

Ref: invert ref guide-j. sprung.  Myrionema/stinging hydroid.
i was quite pleased with them until i found out they are pests. now i feel like i was bragging about a tank full of anemones! Aahh, oh well. all blissful
ignorance must come to an end at some time.
<Embrace the change. Bob Fenner>

Unknown animal, invertebrate, probably hydroid
About myself: for the past twenty-five years I have been a developer of advanced performance materials and only recently started to maintain marine tanks. I have always been fascinated by the marine environment but in the past mostly enjoyed it from a canoe (frequently at night) on the Chesapeake Bay and the Albemarle Sound.
<interesting... and are you a member of the excellent local aquarium society, CMAS? Do look them up.. great club.>
About my tank: the tank in question is a refugium that I could never bring myself to hook up its main tank. It was too fascinating to risk ruining. It is 20 g with Inland Aquatics detritivore and refugium flora kits 20lbs live sand and 10lbs live rock (one piece) 2x65W 6500K PC lights, no filter or skimmer - just a single airstone. After Hurricane Isabel, it went 6 days without any lights or aeration (we had no power). Only obvious loss of life was one very small snail. Upon return of power there was a slight cloudiness that immediately cleared and was followed by a slowly worsening algal storm that grew day by day until visibility was only a few centimeters. Much of my macroalgae died and my copepods began to disappear. At the same time a new animal began to appear in increasing numbers. Here is a snapshot of it:
<a Cnidarian... looks like/is likely to be a hydroid IMO>
It was about 1 cm in diameter and appeared to me to be some kind of hydroid larva.
<agreed... not uncommon>
The algal storm finally cleared and simultaneously the mystery larva disappeared. I now have thriving copepod swarms and a goodish bit of Cyanobacteria on the substrate.
<increase water flow and protein skimming to eradicate this Cyano>
My son and I have looked hopefully for some polyps to appear. We are quite excited by the prospect of finding the adult animal. But so far we have not seen anything new.
My question: What is the mystery larva? Where did it come from? Where has it gone?
<about all I can say for sure is that larvae/medusae were likely carried in with some recent addition (water from a wild source, on the shells of Astraea snails, in bag water from another aquarium with shared livestock that was not (properly) quarantined by you, etc>
What was its relation to the anoxic period, the algal storm and the copepod population changes? What kind of adult animal can we hope to find? and what should we look for?
<time will reveal>
I have feed the tank regularly with shrimp pellets waiting until previous offerings have disappeared. Right before the algal storm, and perhaps causing the storm, I fed with two Spirulina tablets that took weeks to disappear and only after they disappeared did the storm begin to clear. During the storm I did not feed because I was waiting for the tablets to be consumed. With such a heavy storm I felt that there was no lack of nutrients to worry about. After the storm cleared, I resumed feeding with shrimp pellets and weekly inoculations of DT. The water has since remained clear. I test regularly, but the water parameters are always perfect: Ca-400ppm, Total alkalinity-4.5meq/l. No measurable nitrate on a reliable nitrate test.
<do allow some nitrites (5ppm) if you will keep corals successfully long term>
Phosphate is low. I got these results even during the algal storm! I thought some mineral parameter must be off, but I guess that the nutrients must have been bound in organic molecules and not detected by the tests. Of all my tanks, this tank has, by far, the best test values. Also, there is no erosion of the live rock which I see in the other tanks even though I work hard to maintain calcium, magnesium and total alkalinity in those tanks. I have never needed to add any mineral supplement to this tank because the tests have always shown ideal values. (I suspect that the erosion of live rocks in the other tanks is associated with the use of calcium chloride in most calcium supplements. I have been experimenting widely with calcium supplements and I am not happy yet with anything that I have tried).
<I strongly advise the daily use of calcium hydroxide with or without a calcium reactor. It is tried and try and has many benefits over other means of delivering calcium>
I suspect that I tend and feed the tanks rather than the livestock. I don't have many fish: 7 in my 75 gallon and 2 in my 125 gallon. I am fascinated by the water and all the complex interactions between its inhabitants that it is my privilege to observe. I seldom intervene in the tanks except to try to provide stable conditions, light and a modicum of food. I am very interested in the zooplankton populations and have been toying with the idea of harvesting plankton from the Chesapeake Bay and adding them to one of my tanks. At night, when I go canoeing, that are beautiful displays of phosphorescent plankton and medusa.
<yes... a marvel>
I encounter them in small patches. Some patches are blue and some are green and seem to phosphoresce in response to being disturbed by the canoe. I would love to capture some of these and see what happens when they are placed in a tank. It is probably a crazy idea.
<some are toxic as you may know... do be careful here>
I don't know what animals I would be introducing, what their life-cycle would be, or what impact it could have on my tank. I would appreciate any warnings or suggestions for reducing risk that you might care to share.
<all can/will be screened by the proper use of quarantine tanks for all things wet coming in... corals, fishes, snails, algae, live rock, etc... everything please>
Thanks for your attention. I have really enjoyed reading the articles and FAQs. They seem very factual and have proven quite reliable. Karl
<thanks kindly... wishing you the best. Anthony><<RMF lost the pic... pls re-send if you see this. Bob>>

Hydroid hitchhikers 7/15/03
Thanks Anthony. The crab in question finally came out of the rock work again and I fished him out to take a closer look. Since I have the option, what do
you recommend, keep hydroids out of the tank or put them back in?
<in a big enough reef tank, I'd leave them in. Good water quality and they are unlikely to flourish>
The ones on that crab seem to be the only colony. As for Aiptasia, I have had three very small ones that I first noticed about a month ago. They haven't got much bigger in that time and they certainly have not increased to plague proportions as I have read others report.
< a good sign indeed. A well managed aquarium can have them in the display for years with little reproduction. Its all about nutrient control>
However, I am almost to the point where I want to start stocking with inverts in earnest. Shall I remove rock and nuke them while I still have the chance or is good water quality enough to avoid problems later?
<its enough... but then again, most people overfeed or overstock in time. Do remove the Aiptasia to play it safe. And be sure to QT all new inverts, rock, sand in the future to prevent such critters from coming into the display>
By the way, my LFS has several rather large Aiptasia in their tanks. Should one always avoid buying out of tanks like that?
<heck no! good husbandry means QT at home. You can screen most anything from there.>
Finally, if you would be so kind as to offer a personal opinion. In general, would you expect the dual 6" skimmers driven with Rio 600RV's found
on the CPR CY294 to do the job for a 170 gallon tank?
<I think CPR skimmers can be tuned to work very well... but are not so low maintenance or effective as EuroReef's (idiot-proof and excellent). Aqua C skimmers instead are one of the very best values. Two I would put ahead of CPR skimmers>
I expect to focus on inverts and lightly stock with fish. After running the tank for 2 months and with only a couple of LPS and a half a dozen small fish (5 Blue-green Chromis and a Sailfin Tang) plus a full complement of snails and crabs, the skimmer throats are thoroughly coated every day but I get very little liquid in the collection cups. Is that what you would expect with a light bio-load or should I be trying to produce more skimmate even if it looks a little on the pale side. This is my first aquarium, and I have no reference point for comparison. Regards.
<no worries. Best regards, Anthony>

Myrionema... Brown Pom-Pom Hydrozoan 11/20/03
I sent you an email earlier with the wrong picture, sorry. Could you please identify what is growing with my yellow star polyps. They are more brownish than the yellow stars and seem to be spreading quickly. Thanks Anjanette
<the organism pictured is unfortunately a nuisance Hydrozoan of the genus Myrionema. There are no clear predators on this creature to date that we are aware of... manual extraction is necessary. Also control nutrient that fuel it (skim well, do small frequent water changes, careful not to overfeed/overstock. Best regards, Anthony>

Cnidarian ID Myrionema - stinging hydroid 7/18/03
Hi Guys,
<cheers>
I have a very strange algae growth in my 50 gal reef tank (see enclosed pics). I think this stuff came in on some live rock I
bought from a local reefer about a year ago. Now it is starting to take over my tank.
<you have the nuisance hydroid Myrionema from the Pacific. It can sting and burn corals, clams, etc>
I'm wondering if you know of anything to help me rid my tank of this stuff.
<some limpets eat it>
My parameters are:
50 gal reef (no sump)
4 x 96 watt PC lighting
Remora Pro skimmer
Approximately 65 - 75 lbs. live rock
Deep Sand Bed
700 gph water movement (power heads)
S.G 1.025 (refractometer)
Temperature 79-82 F.
Calcium 400 - 420
KH 7
pH 8.1 - 8.4
Ammonia/Nitrites 0
Nitrates 0
Water changes/top offs with RO/DI
Thanks for any advice, Brian
<some manual extraction may help as with a tooth brush tied to the end of a running siphon to scrub and suck the pest out without spreading it. Best regards, Anthony>

Digitate hydroids
I have recently set up my first salt tank and purchased some live  rock.  I noticed that there was some strange come out of the live  rock.  I did an internet search and have found out I have at least two  Digitate Hydroids.  One completely disappears when the light comes on the  other is about a tenth of an inch long.  It is about three inches long with  the lights out the other is about an inch or two.  I have not been able to  find much information on these creatures.  I want to know if they are  safe. << Yes, I would keep them and not worry about them. >> I also need to get a moon light to see what I am missing. << A flashlight in the middle of the night comes in handy as well. >>
Thanks,
Ed
<<  Blundell  >>