what the heck are these

[reeflover1]

I was watching the tank and all of the sudden critters starting coming out of a rock
at least 100 of them they look tiny badmitten
birdies and they pulse when they move
any ideas?????

 

[Aquamans Reef]

Do they look like tiny little shrimp?

 

[reeflover1]

not at all- they look like that may be baby jelly fish sort of

 

[aquakid1]

man i have these things too they swim around the tank continuously..... mine started on the LR then they look like tiny jellyfish. do u have corals and if u do do they harm yours. they dont upset anything but i wish i could get rid of mine somehow ive had them for months and they grow into large numbers?!?
from brendan

 

[aquakid1]

ahah i did it! i found what they are dude!!!
they are called "obelia medusae" i know exactly what u have cause i got em 2!!!!! just keep scooping them out is the only way i can think of to get rid of them.... if u know any other ways tell me plz?????
brendan

 

[wade1]

It does sound like a type of hydroid. What you are seeing is probably the mobile juvenile stage and as adults they settle back to the rock and become sedentary. Sorry, I have no idea whether or not they are nuisances or of no concern, or how to deal with them.

Wade

 

[danmhippo]

A couple years ago, I discovered a never seen before hitchhiker after I planted some caulerpa to my fuge -- Up side down jelly fish. The ones I had back then was brown to tan, largest ones no more then 1/2" across, and smaller one's as small as the ball point on the papermate pens. I literally had thousands of them swimming up and down along the current in my fuge and some made their way into the main tank. The only fish that ate/took a bite at it was the spiny puffers (it was 2" specimen back then).

I am not sure if you are looking at "jellyfish".