What is this hitchhiker from Tonga?

[cjcost]

I have a single piece of Tonga Branch rock that has a hitchhiking coral. It is extremely resilient and the tortoise moves faster than this coral grows (i.e. it grows VERY VERY slow). In about three years, it has grown from virtually nothing (didn't even know it was there for several months) to a couple of 3/4" wide patches on this branch. I've broken that branch off the original rock and had it under 150W HQI 15000K in a 29gal tank for a long time but then tore that tank down and moved to my 120gal which has T5's (dual 250W MH upgrade coming soon).

This corral is currently in the top half of the 120gal placed directly under the lights and seems quite content. Expecting more growth when I finally get the MHs.

Anyways, here are the pictures:

Taken from the front of the tank, through the glass during the morning actinic only period (polyps starting to extrude)

Taken from the front of the tank, through the glass at night with help of a small white LED flash light (polyps are retracted)

Taken from the top of the tank with all water flow turned of at night with help of a small white LED flash light (polyps are retracted)

Taken from the front of the tank, through the glass at night with help of a small white LED flash light (polyps are retracted)

Taken from the top of the tank with all water flow turned of during the evening actinic only period (polyps fully extruded)

 

[roshi719]

Almost looks like an astreopora, but with massive polyp extension

 

[Sikryd]

It looks like Lepthastrea.

See that white patch up on the top of it? I would dip it to see if you got another hitchiker with it. It looks like it could be a not so good hitchhiker - and that is why it might not be growing too well.

 

[cjcost]

That white patch is a section of "dead" coral and then has a spaghetti worm behind that. I've had this in my tanks for 3 years and that white patch is almost exclusively what was there originally then the darker tissue started growing then I started seeing polyps last year. Wasn't until earlier this year that I was able to actually see enough characteristic to try to identify it. I have the 3 Volume set "Corals of the World" by Jen Veron and have looked through every picture several times. Compared against the pictures I loaded here as well as the coral itself. I've found several corals that might resemble the character traits of the coral I have but nothing definite. Even tried compariing the percieved structure of the corallite skeleton where possible. I keep getting stuck on one of the Porites species, but looking again, it does have similar corallite appearance to Astreopora moretonensis, but didn't see a picture of Leptastrea that really matched well. Perspective is extremly difficult to determine in the book though as not sure how close up some of these are. There are a couple Cyphastrea that might be close matches as well.

I may just have to wait a big longer for more growth and possible color development.

 

[cjcost]

Here's a picture that looks very similar to what I have. But, it's not exact either.

Cyphastrea ocelina. coral - Marine Invertebrates of Kaloko-Honokohau National Historical Park

 

[wicked demon]

I have some of that! I was calling it a "mini flower pot" the polyps are the same shape as leptastrea, but get extension like a flower pot. I found a speck of it on a mushroom rock at a pet store, and the owner let me cut it off for $10.

 

[Sikryd]

My first though was porites as well, until I saw how big the polyps were.
Good luck with I.d.ing it

 

[rendos]

Looks like cyphastrea to me.