Amphipod?

[Xavier]

I've found about 4 of these 8-legged "amphipods" on the glass... they seem more stationary then regular amphipods but I'm not sure.. In the attached picture (this is the best I could do for them being about a centimeter across!), the pod in question is on the left, and the regular pod is on the right, just to give some scale... the pod is facing away from the camera, it's "head" pointing in toward the tank... this IS a pod isn't it?

[Satchmo]

Not a pod, it's actually a type of jellyfish called a hydroid. At least that's what it looks like.

[Xavier]

I got a tripod today.. I'm going to try for a clearer picture when I get home... thanks for the info Satch, I'll look up them up and see what I come across...

[Xavier]

Well.. it sounds like a medusa or polyp stage of some Coelenterata/Cnidaria.. whether they advance beyond this stage or not is a good question.. from what I've read, they sometimes do, and sometimes don't.. could be a coral, anenome, jellyfish, hydra, or something else. I'll keep an eye on them.. thanks for the lead Satch!

[Satchmo]

Happy to help. I'm pretty sure it's a hydroid jelly, they're fairly common. You'll sometimes get an explosion of them on the glass and then they'll all just sort of die off.

 

They don't really seem to bother anything in a standard reef from what I've seen. These guys are the reason people with seahorse tanks shy away from using LR/LS. They reside in LR as dormant cysts which will spring to life upon the addition of baby brine shrimp. They are cnidarians, like corals, and do have stinging nematocysts which can make quick work of sensative seahorses.

 

In your case, I wouldn't sweat it. I've seen them come and go in my tank, no harm done.

[Rocket_155]

hydroyd jellyfish nothing to worry about it shouldn't bother your reef at all.