Although the title of the talk did not indicate so, most of what was said related to SPS coralsBelow are some of the salient points to remember where it comes to corals in our aquariums, and their health and well-being:
What can you do to prevent RTN and other diseases?
- It is hard to identify SPS corals in aquariums because when they grow they do not necessarily take on the shapes we are accustomed to due to the type of lighting we use, the water motion and the proximity of other corals. As a result they are hard to ID correctly in many cases.
- The fact that the corals are bright in color does not necessarily mean that they are healthy.
- Acropora is very prone to bleaching or loss of Zooxanthellae. Certain species are more delicate. Get input from your dealer and buy only the hardier types if you do not have a lot of experience with SPS corals yet.
- Rapid growth is a sign of good health.
- Bleaching is the loss of Zooxanthellae and color. This does not mean the coral is dead though. All the polyp tissue is still there. The only thing that has happened is that the symbiotic algae and pigments are gone. These corals still survive but need more care.
- Sometimes the bleaching can be reversed with good lighting, good water motion, and good feeding.
- SPS corals, especially Acropora types, grow rapidly if well cared for.
- The following factors can cause bleaching:
- Stress during shipping.
- Sudden rises in temperature to over 84 degrees F.
- Light shock or the too rapid switch from one type of lighting to another without giving the coral enough tim to acclimate itself to this new lighting.
- Not acclimating the coral for long enough
- Stress due to wrong tank water quality.
- Sudden over use of GAC for too long or in too large a quantity.
- Placing a coral in a shaded area after it has been used to a high amount of light creates stress. So does the opposite. Such changes need to occur slowly.
- There is a big difference between bleaching and rapid tissue necrosis. The latter is loss of tissue whereas in bleaching no tissue is lost.
- In RTN the polyp tissue starts to disintegrate, often at the base of the coral, and sloughs off. If water it directed at it, the tissue detaches from the coral and floats around, the tissue is dead.
- What helps in fighting RTN?
- Large water changes (immediately upon noticing RTN or signs of it).
- By large here we mean 30 percent or more at one time
- Treating the affected coral in SW to which Lugol's has been added. 10 drops of Iodine per gallon of water is used and the coral is immersed for 10 to 20 minutes
- Adding Lugol's to the tank: 1 drop per 30 gallons and adding this every day for several days in row. You can do so in combination with the large water changes mentioned.
- Direct treatment with Chloramphenicol based on the protocol developed by Craig Bingman (see later).
- Cut non affected areas (frag) and remount those in epoxy and get rid of the affected one. Add lots of iodine or Lugol's to the tank to kill off bacteria that are there.
- Dip the frags in an iodine solution (10 drops per gallon) before remounting, and do so for a few minutes at a time.
Greg then went on and discussed other predators. I will elaborate on that in another document that I will add to our web site after my return.
- Buy healthy specimens only
- Buy from reputable dealer
- Don't buy wild stock
- Buy tank raised specimens (e.g. Aquatic Wildlife Company or others)
- Don't overuse carbon
- Do not expose corals to sudden light changes
- Do not expose coral to sudden temp. changes
- Do not place new corals in a tank where disease is present
- Do not crowd the tank
- Specimens should not be too close together. They will grow and in doing so they can prevent light from reaching others that are lower in the tank or right next to them
- Watch for compatibility. Ask dealer questions on incompatibilities. That is why it is important to buy from a reputable dealer who knows these types of corals
- Corals can release toxins and these toxins can affect others that are nearby
- Make sure there is plenty of water movement in the tank. 16 to 20 time the volume of water in the tank as turnover per hour is recommended. In my tanks, says Greg, I turn the water over at least 20 times
- Don't use GAC en masse
- Note that bacteria thrive in the mucus released by these corals (and they release a lot of it). This must be washed off by the strong currents.
- What seems enough current will soon not be as the corals grow rapidly and prevent current from passing through as easily as it did before. Watch for this and increase the current as necessary. 20 x hour is not the upper limit. You can go higher.
- Clean all your pumps regularly as they slow down due to KW and calcium that settles on the inside.
- Load the tank slowly with corals. Go for a gradual increase. Add a coral and when that does well get another one. Do not add many at a time especially not in tanks that are already heavily loaded. Really watch out for this and for good water movement everywhere. Watch that light reaches all areas needed.
- Avoid buying RTN prone specimens. Rely on advice from dealer for this. Another good reason to deal with people who know what they are doing. Read up on the corals you buy. Learn as much as you can
- Quarantine if necessary. You can bathe in Chlorampheniol (you need to get this from a vet. as it is not easy to get).
- Use a solution of 15-20 mg/L for a 20 minute bath. Change 100 percent of the water after 24 hours and redose with medication. Do this especially if you suspect the corals is infected.
- Clean corals well. Mucus should be removed by good water movement as the bacteria that are seen when RTN starts are present in that mucus in very large numbers
- You can also treat in Lugol's: 10 drops per liter for 10 to 20 minutes. Bubble air in that container to keep water movement high.
- Avoid predators and other pests in the tank. This includes certain crabs, little snails (e.g. on clams)
- Watch out for Mithrax crabs
Greg's talk was very informative but did not reflect its original title: Advanced Husbandry Techniques and really dealt with the care of SPS corals.
Earlier in the day Dr. Nadia Ounais showed a real beautiful film of the Monaco Aquarium systems but, as usual, no discussion of the Jauber system took place. This was again veiled in some "mystery". Very nice and informative movie though. Hard to comment on this unfortunately.
Larry Jackson gave a talk on selecting corals and fish. I will cover that in another document and so will I do for a talk by John Brandt on dealing with problems in a creative way.
John Kuhns gave a talk on water chemistry. Info on this to follow in another document.
Earlier in the day, Charles Delbeek gave a talk. I cannot give you a recap as he showed slides of a dive he and others undertook an commented on what they saw and discussed the various corals. It is good to know though that the entire video made of this dive will be shown on the Discovery Channel around Christmas. Very informative and definitely worth seeing. Watch for the Discovery Channel's scheduling and look for the Dive (Richard Pyle was part of the divers).
As you may have noticed all speakers have been focusing on SPS corals and all have stressed the great importance of water movement and building up the load in the tank slowly and paying attention to Light Shock.
To contact Albert J. Thiel About Albert J. Thiel
![]() NetPets® Main Page | The Fish Center |