COTW: Hydnophora Rigida

spsfreak100

Active Member
Hello. I've been asked to do this weeks "COTW." This week, the coral is the Hydnophora.
In my opinion, the Hydnophora Rigida is among one of the hardiest small polyp Scleractinian corals. The Hydnophora Rigida is most commonly collected from Fiji and the Indian Ocean in areas of strong water movement and high amounts of lighting.
Many Aquarists as their first small polyp Scleractinian (SPS) coral often buy the Hydnophora. The Hydnophora is commonly sold with bright florescent green coloration. It's a very attractive coral, which can add lots of color to aquariums. The Hydnophora is a hardy species of SPS, which is able to live under a variety of conditions.
The Hydnophora Ridiga does best under strong amounts of lighting, preferably metal halides. I've kept a few species of Hydnophora under Power Compacts with only limited success. The coral lived, but did not show good growth or coloration. They will most likely survive under Power Compacts or VHO's, but they will probably not be thriving. When the Hydnophora doesn't get enough lighting, it will turn yellow. The yellow coloration is caused by increased amounts of zooxanthellae. The coral will try to produce as much zooxanthellae as it can to try to catch as much lighting as possible in order to live.
From my experience,
The Hydnophora loves strong currents and strong lighting. As with all scleractinian corals, the Hydnophora is Calcium Carbonate based. They will need a steady amount of calcium, preferably around 400-500ppm in order to grow at their best.
While the Hydnophora may be one of the easier-to-keep species of "SPS," it still requires a mature tank with stable water conditions. All parameters including Alkilinity, pH, Nitrate, Nitrite, Ammonia, Salinity, Calcium, Temperature, Phosphates, etc., should always be in check.
You may be asking, "Why Phosphates?" Phosphates will affect the growth of Scleractinian corals. Phosphates will stop the growth, and often make it impossible for the coral to continue to grow. Phosphates should be as low as possible, preferably 0ppm at all times.
The Hydnophora is an aggressive scleractinian. It's best placed at least 3-4" away from neighboring corals to avoid any aggression. The hydnophora is a very fast grower and is able to easily sting neighboring corals, with its long polyp-extension.
If you have a mature tank
with stable water conditions, strong amounts of lighting and looking to venture into buying some Small Polyp Scleractinian (SPS) corals, the Hydnophora would be my first choice to buy, preferably a Captive Raised Hydnophora. Captive raised corals are much hardier than wild caught corals. Captive raised corals also grow much quicker, and are already adapted to life in the home aquarium. Captive Raised corals often do not require "as much" lighting than the wild caught species do.

Please share any other other information, experience or pictures you have on the Hydnophora :) I would love to hear others experiences with the coral, and possibly some pics :)
Cheers,
Graham
 

harrysreef

Member
Good info ... don't have one to show but now my curiousity is peaked about looking into them. I agree lets see some pics
 

nm reef

Active Member
Can't really add to the info...except to testify that they can be kept under less than MH's with success. I run a combination of PC's&VHO's on my 55 and I've kept a Hydnophora Rigida (at least I believe thats what it is) for several months now. Actually closer to a year...it sits top left of my reef in a very brisk current. Since adding it I've seen it nearly double in size. Polyp extension is always full....there is no doubt that they will do much better in more intense lighting. But they can be kept in higher levels of PC/VHO lighting if all other conditions are stable and adaquate. Its very difficult for me to get a good pic of mine due to where it sits but below is a recent shot.....
By the way....I appreciate the help on the COTW graham...good job!
 

nm reef

Active Member
Here is a pic of it the day after I added it. As you can see it was somewhat stressed when I got it...but it has recovered very well and continues to grow at a decent pace.
 

nm reef

Active Member
This next pic is after being in my system for about 3 months...it had just been moved to this location a few weeks prior...and still sits in the same spot...but it is now considerably larger and in much better condition.
 

logan15

Active Member
very nice job spsfreak i love the sps but i want to get a small one when i hope to get some MH for christmas im thinking prob 2 250 watters and ill keep my vho's too
 

jonthefb

Active Member
the horn corals are very cool sps corals with crazy polyp extension making them not look like sps at all! i have two colonies in my 135 in pueblo, both of which have been in the tnak for several years now....a very easy sps to care for, given the proper conditions, and one that grows quite rapidly and that is very fraggable.....
i agree that they do like a brisk current and enjoy high light intensity and are very agressive... one of our colonies in our 150 show at work extended its acotina filaments one night and devoured a small section of a pink birdsnest that was nearby!
good luck
jon
 

spsfreak100

Active Member
NM_Reef & NatureLover,
Nice pictures of the Hydnophora! Great Specimins!
Jon,
I agree with what you've said. They can have extremely good polyp extension if provided with the proper setup!
Graham
 

attml

Active Member
I bought a dying colony from one of my LFSs and wound up fragging it when it began to RTN. I got several healthy frags out of it and here is one that is in my relatively new sps tank. It is just starting to encrust.
 

reef dude

Member
Look what you've all done! now the next coral on my list is Hydnophora! Haha, thanks guys. i believe my tank can handle this specimen. I have 2 175watt halides and 2 40 watt flourescent actinics. As long as i keep it up near the top of the tank, i believe it should do well. Tank is also over a year old, calcium 510, alk is 3.5 meq/L (11 dKH), etc, etc....
-dave
 

fellow

Member
I'd like to mention that Hydnophora is very easily propogated. With attention to detail Hydnophora will thrive immediately and will readily adapt after being propogated.
Hydnophora is also one of the fastest growing SPS corals available. With a high calcium level and good H20 parameters you will love this coral.
 

mlm

Active Member
Here is mine when I fisrt got it about 2 months ago. It has grown since. I keep it near the bottom in a very brisk current.
 

attml

Active Member
Here are a few of the other frags that I saved from the dying Hydnophora colony. They are both growing back over the dead tissue near the base.
 
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