Hydnophora Coral


Bringing an awesome growth pattern along with a very bright lime green color (or even yellow depending on light intensity) the Hydnophora Coral is a great choice for your reef aquarium IF you have the room to keep it away from your other corals. This coral’s sting is seriously strong!

Common Names:  Hydnophora Coral , Branching Hydnophora Coral,  Horn Coral

Skill Level: Moderate

Light Level: High

Water Flow: High

Disposition: Aggressive

Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025

To me the Hydnophora reminds me of a common branching SPS with horns sprouting out all over its body.  The growth patterns on this coral are something very different and unique from other corals which makes it a very interesting coral to own.  On top of the growth patterns, when the coral is kept in the correct conditions, the polyps will fully extend.  These polyps are just as unique looking as the growth patterns.  In the case of the Hydnophora coral which I am showing in this article, the polyps are a bright pink which is neat on its own, but the Hydnophora polyps “balloon” out of the coral and can make the coral appear almost totally pink.

Horn coral with polyps retracted


Picture of polyps extended


Placement of the Hydnophora coral should be in the upper level of your tank for high light and in an area of very high water flow.  The closer you can get your coral to the light without bleaching it you will notice the color gets brighter and brighter.  My frag was taken from a colony sitting very high in a tank near a 400 watt 20k bulb and the coral was a very bright yellow.  Currently, my frag has just been moved into a display tank from a frag tank so it did lose the yellow and reverted to green because I had it placed half way down the tank under T5’s, but it’s still a very pretty coral even if it never regains the yellow.

Hydnophora Corals are a photosynthetic coral and do not need to be directly fed. The coral produces its food from the lights on your tank. The polyps will occasionally catch food in your tank but its main source of food is through photosynthesis. Feeding this coral directly is not needed; I have tried but never with any success so I don’t even try anymore.  I now treat this coral like any other SPS except I make sure to not let it touch any of my other corals again ( see below).

After I had picked up my Horn Coral, I had placed it first into my quarantine tank (very important!). After a few weeks when I couldn’t find anything wrong with the coral, I moved him over to my frag tank. He didn’t go directly into the display tank because I didn’t have a place for it yet.  I assume while I was messing with the flow in the frag tank one day I didn’t realize the frag had swung around to face a different direction.  The next day I noticed it was touching a Favia coral frag.

Here is a picture of days one through four where the Hydnophora coral touched the Favia frag.

Day 1

Day 2

Day 3

Day 4

Day five was when the tissue loss finally stopped spreading, the heads left alive were very upset with me.


As you can see by the images above, you need to take great care in keeping the Hydnophora coral from reaching your other corals. Its sting is very potent and I can see it easily killing off any corals it can touch.  I described its extended polyps earlier as balloons but what I meant to say was nuclear missiles.


Propagation of this coral is handled like many other SPS corals.  While my personal piece is too small to frag, I have seen friends frag theirs and it’s handled just like any other branching SPS: basically cut or break the coral where the branches begin to “fork” off.  Once the piece is removed, glue it onto another piece of live rock or a frag plug. It’s okay to have your coral out of the water for several minutes.  Once the glue is dry, place your rock back into the tank.  Give your coral several days before you begin to see full polyp extension.



Hydnophora Coral Growth Shots

Hydnophora-2012-08-02 (4)



3 thoughts on “Hydnophora Coral

  1. Hello
    I HAVE A branching horn coral and have had it for almost a month it had started to retract more often. I havve slowly brought it higher in the tank it helps the poylps come out for about a week and then they start staying retracted again. I have leds that are dimmable they are prolllly around 20% right now. I’m affraid of bleaching it. What should I do.

    1. Hi Edward,
      Moving the coral itself closer to the light will change the coloration of the coral itself but overall will not help with polyp extension, it may make the Polyp extension retract even more in my opinion. Would you say that right when the lights come on you notice the coral has good PE (polyp extension) but as the lights are on longer that’s when you notice the PE begins to decrease? For the most part this is normal, you will get better PE through the night when the lights are off , and gradually as the lights are on the PE will reduce. Is this what your seeing or is it more of a reduction over several days which i think you may be implying.

  2. What is the growth pattern of a Hydnopora? Do they spread out or grow up? How much head space do they need on above the top of the rock structure?

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