coral of the week { Galaxea }


Premium Member
week #12 coral of the week {Galaxea}. This coral is pictured on page 86 of the book Corals a quick reference guide by Julian Sprung. This Coral puts out some huge sweeper tentacles. Its easy to propagate by fragmentation. A lfs by me had a big colony and around it were about 1/2 dozen frags.

Every week I will post a new coral and I want you to post everything you know about this particular coral. Everything from common names, how hardy they are, water temp, water flow, lighting, water parameters, fraging, spawning, related corals, scientific names, feeding, best ways to ship, etc. Post your pictures for identification. Please tell us about your system so others can duplicate your success. Also email me for request on which corals you would like to see in this section.



New member
I spotted a galaxy about a year and a half ago at Harbor Aquatics that was oblong about eight inches by six inches, with two hills, in between these 'hills' the tissue receded. My plan was to break the light skeleton into two, but I never got around to it, due to placement concerns. (The sweeper tentacles, in moderate current, appear to be about 4" in length.) I kept it in in high light (2-250 Iwasakis, & 6 55W PC's) mid-height in a 75. The current ruffles the polyps gently. In a few months the tissue between the hills had covered the bare skeleton, even over areas on which coraline algae grew. It grew quickly, now near a 12" by 9" oblong shape, and the 'hills' have grown up another inch or two. They are very pretty corals, especially under actinics. The polyps appear to close some during darkness. Mine didn't seem to respond to food. I've dosed DT's phytoplankton for quite some time, but don't know if this coral benefitted. Temps average 80F. My alk and calcium have always been pretty high, and I'm currently running a CA reactor. Spreading Montiporia Digitata appears to be growing into the sweeper tentacle range, but appears to be unaffected.
Galaxia!! Very beautiful coral, and very deadly IME. I had a couple of these early on in my reefing experience, and ended up trading them or returning them to the lfs. They have long sweeper tentacles and the sting is very toxic to other corals. IME they need a lot of room with no other corals in the neighborhood.

I now have a 135 gallon reef, but still no room for one of these guys. Maybe when I get that 1000 gallon custom-made sweetheart.....;)


New member
Yes, let me second Larry's comment. The only factor that has saved me from the sweepers has been placement on a Tonga slab in the corner of the tank. In the near term, I'm upgrading to a 180g, and it is destined for an open spot in the sand. Higher current causes the sweepers to lengthen.

I've read about the toxicity of the sweepers in many texts, but in my experience (or just dumb luck) they've seem to have had no effect on Horn coral or pipe-organ coral for some reason. As I mentioned, I'm worring about the growing proximity to the Montiporia Digitata, and hope to upgrade the tank before that is an issue. However, I wouldn't recommend keeping a Galaxy near other corals.

[Edited by Jawfish on 02-14-2001 at 11:28 PM]

Dan Lee

New member
I have a small (3") galaxea frag I won in a raffle. I've had it about a year, and it hasn't grown much (I think this is an exception rather than the rule... Stuff in general doesn't grow very fast in my tank, not even green stars... m. digitata seems to like my tank the most).

The galaxea cemented itself to a rock and has its polyps out pretty much all the time. I put it next to the tank overflow so its sweepers would be swept away from everything else. For the first few months it put sweepers out at night, though I haven't seem them out in recent memory.

I'll move it out of my tank (it's a 50G) if it gets too big, though at its current growth rate I that'll be in like 50 years or so.

I don't feed it. It's living under 2x96W PCs and 4x95W VHOs.