What the heck is this on my glass?

[trybry5]

I have Copedpods, baby Amphipods on my glass. Then when the Cope's get plentiful, here come these guys by the hundreds.

Once they appear, the Copes, numbers go way down. Never could catch them eating a Cope, but they come and the Copes go.

Can anyone ID. these guys?

Thanks

 

[<3Oscar]

kinda looks to me like a mini jellyfish. i've read about them before and seen visuals similar to what you are showing. As far as I know, they are harmless. But I could be wrong. Melevsreef has the photo I was thinking of, check there and see if his clear shot is similar.

http://melevsreef.com/id/special.html

 

[fsn77]

Hydroid jellyfish. They are pretty common in newer systems and typically disappear completely after a short period of time.

 

[trybry5]

I guess so,

It has plenty of tentacles or tendrils? They don't seem to move much or swim. But they do ride the currents to get around. Nothing seems to want to stay in contact with those tiny arms too long. They hang on the glass and wait for the pod to bump into them.

Thanks for the reply

 

[trybry5]

Wow,

Thanks!
They must travel with the Copedpods or Macro Algae, I got this year.

I'll read up on the Hydriod Jellies, hope they won't bother my new purchases (Gold Watchman Goby and Matted Filefish).

The tank has been up and running for 8 years. I just never bothered to replace the fish or clean-up crew.

A Power failure, triggered over heating of water by the heater years ago. Took me awhile to want to get more fish. Will need a better heater by the fall.

Thanks again

 

[Manolin]

I agree with fsn, it looks like a hydroid. I've read that keyhole limpet snails (Diodora cayenensis) eat them but if you have any corals in the tank, the limpets might graze on them.

That aside, you could probably wait out the hydroids - they're filter feeders so as your tank ages the water should clear up and the hydroids should starve to death.

P.S. I just saw on your follow-up post that it's an 8 year old tank. I would guess then that the hydroids just got recently introduced with something new you put in the tank and they'll disappear in the next little bit.

 

[waynotcars]

They sure are COOL looking!

 

[trybry]

All the Hydriods, are still hanging around.

But I haven't had any newbies (new additions), in months.

Those driods are now clear bell shaped jellyfish about a 1/4 inch high and wide.
They rest on the glass as babies and on the substrate, as adults. That is until the crabs or snails disturb them. Then they pop up and float around for a few seconds.