Unknown invertebrates infestation - pls help

[velinski]

Hello,

I have nasty new invertebrates in my aquarium which appear from a live rock probably about 4 months after starting my saltwater tank in April.

They look like small white "worms" (about 4-6 mm long, 2-4 mm thick) with a small "crown" at top of very thin hair-like tentacles. The "worm" has hard body, glued to the live rocks, side glass of the tank and mainly - in the canister. They prefer to grow at total dark or at places with reduced lighting.

I tried twice to kill their population mechanically but without success - they pop-up again in about 2 weeks. I was forced to throw out the filter media from my canister and 2 big live rocks from the tank because the "worms" were made a huge population there.

Please help me to identify this animal (copepod? worm?) and give me some ideas how to get rid of it. I am very concerned about my tank.

All water parameters are normal - temp. 25 deg. Celsius, salinity 1.0245, O2=4mg/l, pH=8.2, kH=8, NH/NO2/NO3=0mg, PO4=0,15mg.

My tank is 170 litres, 1100 l/h filtration by outher canister and about 2100 l/h inner water circulation, AquaMedic Miniflotor scimmer, 15W UV-lamp, and no sump.

This is the invasion in my canister:

 

[mbbuna]

there sponges, good to have. some people call them pineapple or cue-tip sponges i beleave there real name is Sycon

 

[mbbuna]

O and

[welcome]

 

[boomsticks]

Yes they are a good sign that the water quality is perfect too.

 

[Reefmack]

Scypha sponges:

http://www.melevsreef.com/id/sponge.html

 

[seakwon]

i have thousands of those, im glad they are good for the tank but they are a pain in my butt. whenever i want to clean anything they get in the way. they hide on really odd places where my fish cant get to. i dont know if a puffer would eat them but i think mine did.

 

[velinski]

Thank you for your (positive) response!

Sounds great the sponges are harmless, but they look really nasty.

 

[NanoReefWanabe]

my sump has thousands of them in it...as does my overflow...they seem to like low light areas in my tank....

 

[LeslieH]

If you decide to take them out & you're thinned skin be sure to wear gloves (a good idea in any case). Those fine calcareous structures called spicules have needle-like tips. They may penetrate skin, resulting in swelling & itching or worse. Here's a picture of some:
http://www.cbu.edu/~seisen/Porifera/sld004.htm

Sponges are constantly pulling in water through channels in their bodies, filtering out the organic particles & dissolved organics, then pus the water out through openings called oscula; one opening is an osculum. Scypha sponges only have one big one at the end of the body. (http://bio1152.nicerweb.com/doc/class/bio1151/Locked/media/ch33/33_04SpongeAnatomy.gif) That's why they're so good for tanks. With enough sponges you could have all the water naturally filtered without using a filtration system but there wouldn't be room for anything else.

More info on sponges here: http://reefkeeping.com/issues/2005-07/rs/index.php