View Full Version : could there be jellyfish in my tank

02-25-2010, 06:37 AM
OK so I bought 50lbs of live rock from some guy and on the rock their is some small little polyps that move and look like jellyfish and they are detaching from the rock and starting to swim in in the water they look exactly like jellyfish. I used a flashlight to look at them better and they seem to follow the light all of them gathere righ under the light. Are they bad in my tank and can they be taken of the rock easily. I am afraid to place the rock i my display tank they are in a rubbermaid container at the moment. i tried taking a picture of them but they are way to small about 1/8 of an inch is the biggest one i saw. Does anyone have any advice

:sconfused: :sconfused:

02-25-2010, 07:33 AM
Unless they are a photosynthetic species, there won't be sufficient life to keep them fed, so they'll fade away in a week or so. If they are tiny as you describe, they aren't a danger.


02-26-2010, 01:22 AM
or you could just let them be sucked up and out with the filter, they may not survive.

03-09-2010, 07:25 PM
I have been keeping them in a rubbermaid container with powerhead and live rock and they seem to be growing. some of them have even started getting white spots in the disc part. I have also noticed that the tenticles are also getting longer its cool watching them swim around with moonlights on them

03-09-2010, 08:25 PM
Super neat. Try to get photos !

03-09-2010, 09:38 PM
They are hydroid jellies. They are very common hitchhikers but most people dont see them cause they get succked up in filters.

03-10-2010, 10:06 AM
That's utterly amazing! :ssuprised:
I am a big fan of jellies after seeing lots of different type of them at the aquarium. You lucky thing being able to spot them and have them!

03-10-2010, 12:10 PM
I wouldn't call it lucky necessarily. Hydroids are not good hitchikers as they can sting your corals. Fortunately they do not usually live long since there is generally not sufficient food for them.

03-10-2010, 12:44 PM
^very true

03-15-2010, 04:37 AM
Ah, I see - that is most unfortunate as they seem cool creatures as well. :scry:
Very interesting read this thread though! :ssmile:

06-17-2010, 05:57 PM
Hey.. i had the same thing happen to me and i started looking into it .. i found there is a spices of jelly fish that are rather small that are called Cladonema my tank was well estlibshed at the time i added the rock and i've had no problems...

here is a link you might find helpful.. =)


hope this helps!!!

06-17-2010, 05:59 PM
Pics would be awesome.thumbs2: