Another strange cnidarian of some sort...pretty hitchhiker.

[Anonymous]

I found this in my refugium at home, and moved it to the nano. It only expands at night so I was lucky to see it. I found another identical one attached to a piece of activated carbon in my sump, so it may be reproducing. Obviously some type of cnidarian, but I've never seen one before. Pretty sure it's not mojano or aiptasia...Good? Bad?

 

[Anonymous]

It's about 1/4 " across in this picture.

 

[TZL]

i'm guess Hydroid....a type of jellyfish....not good for your reef....dangerous stings

 

[investigator1]

Hydroids have thinner and more elongated arms.

Here's an example to further clarify.

 

[Anonymous]

I am going to guess it's a corynactis - cup coral. I see lots of them on fla/carribean live rock - is this from the Pacific? I know they are circumtropical and mostly non-photosynthetic.

 

[Anonymous]

The rock is from all over, mostly Fiji but also some secondhand from another reefer. While breaking down my tank I found two more. Not exactly a prolific spreader so I'm not too worried.

The corynactis californica we have opens up even under intense light, and this thing doesn't. Otherwise, though, their appearance is very similar. I couldn't find pics of any corynactis species other than viridis and californica, both coldwater.

 

[ReefRian]

Matt,

Not sure what they are either, but I've got about 20 in my tank. I've had them for at least 4 or 5 months and have never seen a problem. Mine normally don't open until the lights go out. They do reproduce rather quickly. I have about 10 on one rock that has a single mushroom and at night when the mushroom closes up the rock is covered with these. It's amazing, I think beautiful.

Rian

 

[Anonymous]

Pseudocorynactis caribbeorum

Page 321, Delbeek and Sprung's "Reef Aquarium" Volume two. They're also on the cover of the book!!