Simply Speaking

By, Tom Miller

Captive Reef Propagation Series

Part IV: Coral Reef Gardening - Grow Your Own Stony Corals, Live Rock and Live Sand.

The time has come to spread the word that fully propagated reef aquariums are already a reality. We still have a little way to go before we can raise really spectacular reef aquariums ourselves, but they are and have been possible for some time. We are still limited on some stony corals. Of course we still only see a modest variety of tank raised fish available. I hope that many of you will set up totally propagated reef aquariums. I'd like to see pictures of them. I'm sure others would too. Is this the next craze? Maybe not. I am still "all for" responsible, reef friendly farming of the oceans for collecting aquarium specimens. I am just excited about tank- raised propagation too.

Last month we finished exploring several ways to make cuttings to propagate several varieties of soft corals. I've already received correspondence, regarding the first two articles in this propagation series, from a few people that are making and growing coral cuttings. Some of them are doing so for the first time. First timers seem to be a bit nervous, but that's all right. I was too when I started. Once you get going, it's really a lot of fun to "plant" and grow your own coral reef garden. Experimenting with techniques and trying variations can be rewarding as well.

Let's start with stony corals and then tie it up with live rock and live sand growing. When we talk about stony corals, we are talking about corals that are reef builders. They grow a calcium-based skeleton underneath or inside a fleshy covering. As they grow and eventually die, they leave behind white skeletal structures of varying shapes and sizes. These can become encrusted with other life forms including coraline algae and even new corals, shells and so on. In the ocean this builds a coral reef. There are two types of stony corals that we'll propagate. The first type is the SPS (Small Polyp Stony) coral group that contains such common corals as Acropora, porites, montipora and pocillopora to mention a few. Many of these are branching staghorn-like corals. Many hobbyists call these "acroporid" corals in a loose sense which refers to them being like the popular branching coral Acropora. The second type of corals we'll propagate are the large polyp - stony corals like elegance, brain, flower pots, frog spawn and bubble corals just to mention a few of their common names.

First we'll look at SPS coral propagation. Some of these often branching type corals are fast growing, up to 6 inches per year. Others are much slower growers. Acroporid type corals seem to be of very high interest to many hobbyists and are surprisingly (to some) the most easy stony corals to propagate! One method that I do not necessarily recommend is to accidently drop a nice big well-branched specimen on the floor or on a table to break it up into fragments for propagation. This has happened to many hobbyists by accident. The ones who pick up the pieces and put them in their tanks notice that most if not all of them grow new branches and attach to rocks on their own! This leads us to the more common method of purposely breaking or pruning off branches from a larger or overgrown specimens to obtain cuttings to make new corals. A pair of diagonal cutting pliers is ideal for cutting off brittle branches of SPS corals.

We usually don't want the cuttings to sit loosely on the rocks in our reef aquariums to get knocked over, roll around, fall and get lost. Let's fasten them to rocks. You can use existing live rock, base rock, aragonite rock or make your own cement rock like I discussed last month. Remember the recipe for "easy no-bake coral cookies." To attach the Acroporid cuttings, we can rubber band them to the rock laying on their sides or use fishing line to tie them on. The tiny polyps will spread onto the rock and new branches will sprout upwards from the old one. This sounds a lot like plants. Growing photo-synthetic coral is just the art of growing algae - the chosen type of algae of course. This means single celled symbiotic algae that grow inside corals' cells called xooxanthellae (commonly pronounced: zoh-zan-thehl-ee). It can become a balancing act or even a war at times, to encourage fast growth of xooxanthellae algae, but not hair algae at the same time. Besides proper lighting, water conditions and water flow, feeding can also help many corals really thrive.

Speaking of water flow, branching SPS corals love good water movement. According to Richard Greenfield Jr. of CaribSea (AKA the "Sand Man" - aragonite sand of course!) branching Acroporid corals and many others are accustomed to tremendous water flow rates near reef crests in the ocean. He has observed very healthy SPS corals being blasted by irregular wave action of one to two meters per second. We wouldn't dream of this in our aquariums! But actually, Richard (Rick) has dreamed of this kind of wave action in his aquariums and IS experimenting with very high water flow pumps. Imagine the turbulence of churning 100 tank volumes per hour though your aquarium pump(s)! That's 2000 gallons per hour for a 20-gallon tank!!! Does he get any water on the floor doing this? Folks, don't try this at home - without adult supervision of course.

You can also attach branching acroporid coral cuttings in an upright position by using underwater epoxies molded around the base of the coral's stem and then molded onto a rock. The easiest method of all is simply to use Super Glue gel! Dry off the base of the newly cut coral branch and the spot on the rock where you want to glue it. Just put a glob of super glue gel on the rock and then stick the coral branch on it and hold it a few seconds. Put it under water to set up. If it falls off, just stick it back on and move it around a bit to form a stringing action that helps it bond. Some people purposely stick and unstick the coral a few times to encourage this stringy bonding action. Others just put the Super Glue on the coral base then stick it under water and onto a submersed rock. Then they give the coral a quarter turn twist to help the glue set up. Slimy rock doesn't work well here. Brush it off or pre-scrub the slime off the rock with a tooth brush. Despite the fact that Super Glues had been used for years before GARF used it, Super Glue was still rumored by many to be unworkable for under water use. The Super Glue research team at GARF (headed by Mark Barnes and Larry Read) went ahead anyway and helped to further Super Glue attachment suitability research and found that it really does work quite well in many cases. Mark also found that the new gel type Super Glues work better than the old runny Super Glues. He spent countless hours testing various super glues (Cyano Acrylate glues) at GARF and came up with a couple that work better than the rest. They are of course the thickest ones! Mark now markets the very best thick glue that he found under the name of "Super Reef Gel". You can contact Mark at ReefGel@aol.com for prices.

Super Glued cuttings will not only grow tall and branch out, they will also grow down onto the rock and spread out into a flat disk of polyps around the base of the coral branch. Some growers then break off the branch at the base at a later date to provide more cuttings. The remaining flat disk that is left behind will grow new polyps over the bare white stump. Next, new branches will shoot up all over the remaining flat disk.

Besides good water movement, these branching SPS corals need good lighting. Placing a nice specimen under and between two German 10,000 K 175 watt metal halide lights will illuminate the specimen on both sides so that a shaded side is mostly eliminated. This is considered by many to be the ideal artificial lighting as far as spectrum and intensity for such corals. Nevertheless, not everybody agrees. High-power flourescent tubes can also provide intense proper spectrum lighting to all sides of a branching SPS coral to keep otherwise potentially shaded sides from dying. I have seen very good results with VHO and Power Compact flourescent lighting systems.

Once again, I'm going to disappoint many sceptics by saying the seemingly absurd. I have nothing against the previously mentioned, really nice, fancy and expensive lighting systems. The often obscured fact is that 40 watt flourescent tubes can also grow good, if not fantastic, acroporid corals! Uh-huh, you heard it right here. No need to go into shock over this controversial "news." LeRoy Headlee, Ray Brown, Mark Barnes, Merrill Cohen, I and others have and do successfully grow acroporid corals using two to six 40 watt Triton and Blue Moon Reef flourescent tubes. Using two or three of each tube is best (four to six total) with Triton Enhancers (mirrored reflectors) or other real mirrored reflectors in your aquarium hood for best results. For example, in a four foot long tank, place the corals higher on the reef rock structure in good water current, preferably alternating current. Two power heads on timers could provide this. Place the corals anywhere in the top central two feet of the tank for best lighting of all sides of the coral to prevent shaded areas and die-off. If the tank has a wide central support beam or central supporting piece of glass, don't place the coral right under this or it will be too shaded. Don't use glass or acrylic tank covers either. Do use water proof end caps and clean the bulbs of salt spray regularly. Make sure they can't fall into the water while being manipulated or worked on. I have watched a mostly brown Acropora with a slight green cast turn mostly bright green under this lighting in my own home. The Triton/Blue Moon combination definitely works better than other 40 watt flourescent tubes (that I've seen or used) to improve the health and coloring of corals in general. You CAN raise Acroporid corals on a budget.

(Note: Some SPS corals grow slower than others under standard 40 watt flourescent lights. It is best to place them high in the tank, close to these lights for good growth. However, montipora and pocillopora seem to be the most tolerant SPS corals of lower light conditions. Even though you can grow these two types of SPS corals under virtually any lighting, they do grow faster under brighter lighting!)

One idea I've heard from several sources, is to grow SPS/Acroporid coral cuttings in a farming situation using metal halide lights that move on a track overhead. This simulates the daily movement of the sun and lights the coral cuttings on both sides over the course of a day. This is certainly an ingenious idea and should help with the survival rate of new cuttings. It reduces shaded areas to reduce die-off. This may be nice in nature or on the coral farm but this doesn't solve the problem for the hobbyist who takes these branched SPS corals home, putting them into his or her aquarium only to watch the undersides of the branches die off anyway. You don't need to have lights that move on tracks or "swing from the rafters" in your home. Just be aware that proper placement under fixed lighting will reduce die-off. This is possible if you follow the advice in the preceding paragraphs.

Calcium and strontium levels are important to the health and growth of SPS corals. Preliminary tests with SeaChem's Strontium and calcium test kits show that CaribSea Reef Sand provides the necessary levels of calcium and strontium. In fact, the strontium levels are quite high in eight tanks I have tested that have aragonite sand in them. Proper pH and KH are important too. Again, I don't use kalkwasser with aragonite, but a light dose (1/4 of the recommended dosage) of Reef Builder from SeaChem seems to give a little extra growth boost without binding up your aragonite. Also, another good alternative is to use a little bit of E.S.V.'s B-ionic calcium buffer supplement to do the same. This raises the KH/alkalinity just a bit and can speed up growth of SPS corals. One more alternative for speeding up SPS growth is to hook up a calcium reactor which forces a tall column of aragonite to dissolve more quickly, buffering your system to higher than natural levels, which again accelerates coral growth. Now we're getting away from simple solutions and into high-tech stuff that is impractical or unnecessary for most home aquariums on a budget. Let aragonite sand naturally do its job for your aquarium. Calcium reactors may be more practical for a larger farming operation though.

It is now time to check out propagation possibilities of large polyped stony corals. Some of these corals will often put off new polyped buds that can detach and grow a new coral. Some varieties that do this are Catalaphyllia (elegance coral), Euphyllia varieties (like frog spawn, torch and anchor corals), Plerogyra (bubble corals), Trachyphyllia (open brain coral), Favia (closed brain coral) and Goniopora (flower pot coral). This is a partial list of more common varieties that reproduce asexually. Many of these corals and others, including SPS corals produced planulae spontaneously on their own that can settle next to the parent or on other rocks or glass, growing new corals. When some corals die, they release planulae in an apparent self propagation/preservation attempt. I have seen examples of frog spawn and bubble corals doing this as they fade away. Don't throw away that dying bubble coral. Watch for new little 1 mm six bubbled polyps to appear on the newly exposed fins or next to the old coral polyp. The underlying rock that these small new polyps are attached to can be chipped off later with a sharp knife or a cold chisel and attached to a new rock with a Super Glue gel or marine epoxy. They don't grow real fast, but you can end up with a polyp after one year that has grown a base ½" - 1" across. Of course the fleshy polyp expands even larger.

Larry Reed of Boise, Idaho has two large flower pot corals that have done very well in his aquarium for four years. During this time they have popped out dozens of buds or young new corals that seem to be an aquarium-hardy variety. What are his longevity secrets for this often difficult coral? He places them about 1/4 of the way in from the bottom left front end of the tank on the sand. What does this "hocus-pocus" formula have to do with the science of keeping corals? It appears that it does make sense because of three factors. First, the coral is on the sand just like its natural habitat. Second, Larry uses VHO flourescent lighting. Flourescent lights produce a bright spot about 1/4 of the way in from the ends of the tank. To show this, look down the inside front of the aquarium glass to see the effect that these bright spots have on extra algae growth on the glass. The corals are in this well lit spot and are lit from both sides. The third factor is the water movement that is adequate but not too strong. It naturally fluctuates a bit in this location causing the tentacles to gently wave. The nice current brings the coral food, to supplement photosynthesis, and provides proper movement to the coral which helps its internal circulation. The lighting seems ideal in this location. Or, maybe he just got lucky and has a special variety that does well in aquariums. Could it be some of each? Rumor also has it that since goniopora live in colonies on the sand in nature that they seem to do better in colonies in a tank. See the picture of Larry's tank with a group of small to large goniopora on the sand on the left side of the aquarium.

Polyp bail out sometimes results in an existing polyp becoming a new independent coral as it grows a new skeleton. Meanwhile the polyp may not weigh enough to settle down in a good location without getting blown around and stuck in an unreachable location in the shade where it may die. I have watched this with bubble corals. Sometimes the polyp can be put in a cup where it will not blow away until it develops enough skeletal mass to hold itself down.

On a related tangent, large polyp corals with multiple polyps can be broken or sawed apart between polyps. This often gives the individual polyps more space to spread out and thrive. Some people have even gone as far as to saw large polyp stony corals such as brain and elegance corals into a few pieces that heal and become separate corals. This may not be the most ideal method of propagation. Leave it to the pro's. Aquarium conditions must be ideal for these pieces to properly heal without developing protozoan infections and dying.

That's about it for coral propagation. To have a fully propagated reef aquarium we need to know how to make live rock and live sand, or at least know someone who does, or where to buy it. Live rock is easy! Or, at least what some hobbyists call coralline live rock, is easy to make. This is beautiful live rock encrusted with coraline algae of different colors including greens, pinks and purples. The most common homemade coralline rocks usually start out dominated with green micro algae and even coralline encrusting algae but get taken over by the purplish varieties of coralline in the end. Like I've said before, it's as easy as putting pieces of aragonite rock or special reef safe cement rocks in a tank full of coralline encrusted live rock, then waiting for the coralline to spread and grow on the new rocks too. Use the recipe for "no-bake coral cookies" to mix up special cement and make it into bigger rocks.

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ABOVE: Author's 180-gallon acrylic tank with coralline growing on the front "glass."

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Just as coralline algae easily spreads to the aquarium glass in the picture of my 180-gallon reef tank, it will also spread just as easily to your new rocks. It can take four to eight months to get a really great looking coralline rock made from scratch, but sometimes much more quickly. The large mushroom rock in the picture of my 29-gallon tank raised reef aquarium is only two months old. Not all rocks grow coraline algae this fast. The mushroom rock grew coralline faster because I scrubbed the coralline algae off the aquarium's glass (actually acrylic) which I started it in - the 180 gallons pictured with coralline growth. I used an acrylic safe scrubbing pad which really turns the scrubbed coraline into "dust." This created many loose spores to settle on the new rock, starting its growth faster. I also started this rock out under bright metal halide lights then switched it to just a single 20 watt Triton after a couple of weeks. Many aquarists report that starting rock out under bright light or fast current helps get the coralline started as tiny little specks of color. Nevertheless, we have noticed that these coralline specks seem to take off and grow faster when the light level drops somewhat. Move it either from the top of the tank, down to the bottom of the tank, or to a tank with standard flourescent lights for a possible boost in growth rate.

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ABOVE: This is my own 7 month old 29-gallon reef tank which has 100% tank-raised live rock, all of which is less than the age of the tank (mostly 4-6 months old), and grown in this tank with the exception of one rock. The large mushroom rock (front right)is just over 1.5 months old in this picture! It was started in another tank with stronger lighting and then moved to this tank after the mushroom anemones attached and the rock was not much more than 2 weeks old. When first moved to this tank, this rock had small splotches of pink and purple coralline algae starts all over it, but the rock was still mostly white/beige and greenish looking when moved to this tank. No calcium supplements or buffers were added to this tank. Trace elements in low doses were all that was added to this tank. Calcium, strontium, magnesium, and buffering are provided by the tank-raised live sand made from dry bagged CaribSea Seaflor aragonite Reef Sand. The coralline algae would grow even faster if this tank were receiving the same additives as the 3 reef tanks shown above. This 100% tank-raised reef aquarium has NO red-legged hermit crabs (C. digueti) to impede coralline algae growth by eating it.

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ABOVE: Valerie Miller's tank-raised "xenia forest", shown about 6 months before this article was written. It has GROWN since this picture! There are four types of xenia shown above in her 75-gallon reef tank. Also note: The large concrete rock is kept nearly clean of coralline algae, looking dull gray-green. Other rocks are lacking in really good coralline growth too, a classic sign that certain hermit crabs are present which eat more coralline than you might like them to. Coralline would normally be quite obvious and starting to flourish on new concrete rock by the end of two months in a reef tank like this rock has been. The other tank-raised rocks are a year old. Coralline growth is still somewhat lacking, even with just a modest number of Mexican red leg blue spot hermit crabs present (C. digueti) which are cleaning the rock of alga, including coralline algae. In the past six months the number of hermits has decreased due to natural die-off and cannibalism. The pink, mauve and purple coralline algae is growing better now. In another test I performed, I put two small uncured concrete rocks in two HANDY Reef tanks with identical dosing and care. One tank had a very modest number of C. digueti hermit crabs in it and the other tank had none. The concrete rock in the tank with none of these hermits became almost totally covered in coralline on top and sides within just 2.5 months! The new concrete rock in the other tank, with C. digueti hermits, was still struggling to grow coralline algae, with very little coverage of coralline algae even after 6 months! The grey concrete changed colors, to a dominant gray-green look, like the picture above. The C. digueti hermits tend to keep new rocks cleaned of coralline algae the best. Another interesting observation was made. As expected and often observed elsewhere the coralline growing on the glass of the tank with C. digueti hermits was slightly less dense than in the tank without these hermits which had much more coralline already growing everywhere since there were no coralline "preditors" present. Remember, the more coralline in a tank the faster it spreads to new rocks and the glass. The coralline growing on the glass of the tank with the hermits eventually grew so thick that the hermits were finally able to climb the coralline covered glass and start stripping it too! All of this should come as no surprise since these hermits have been extensively observed to eat coralline algae in addition to their diet of snails and even coral polyps. They are omnivores of course and this should also be no surprise. In live rock farming it is critical to NOT include certain hermit crabs which eat coralline algae like candy. Claims to the contrary should be a red flag as to the honesty or knowledge of such claimants.

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Coralline algae isn't the only thing we need on our live rock. The real value of the live rock is in the diversity of life that lives inside and on the rock. This includes not only algae, but bacteria to process waste, and a wealth of micro crustaceans (and worms) that multiply from your existing live rock to populate your new live rock. The most notable micro coruscations are amphipods, decapods and copepods that multiply by the thousands (or more), providing janitorial services to the rock and sand. They are also a valuable food source for fish, corals, sponges and other filter feeders. Mandarin gobies and scooter blennies won't survive long in your tank without these live food sources. Live sand also provides a natural habitat for these bacteria and tiny crustaceans. Live sand and live rock are mandatory for a healthy reef tank.

You can stack up a whole tank full of "dead" rock and use a few pieces of live rock to seed it with all the good stuff. To speed up coralline algae growth, give the tank good rapid water movement that spreads coralline algae spores. You can even put a nice coralline encrusted rock about a foot in front of a strong power head to help spread it faster. You can also take a coraline encrusted power head strainer from an existing tank and install it in the new rock propagation tank to help. Also, you can scrub a coraline rock with a toothbrush in the new rock tank to release a good starter culture. If raising a tank or a tub full of live rock with no corals or fish, still add just a little fish food to help the growth of the bacteria, micro fauna and coralline algae. Also, remember to use a nice thick layer of CaribSea aragonite to provide calcium and other elements. Supplements such as SeaChem's organic Reef Calcium can accelerate coraline growth. Many people are reporting accelerated growth from using Marc Weiss' Coral Vital.

Lighting for growing a tank or vat full of coralline rock can and should be kept very simple. To illustrate this, I'll tell about my failure to grow good coraline rock in a kiddie pool outdoors last summer. You may want to try this, but with the recommended modifications so you can succeed. I used two to three inches of CaribSea aragonite Reef Sand on the bottom of a foot deep by five foot diameter round kiddie wading pool. I then stacked Idaho aragonite rock all over on top of the sand and filled the pool with salt water. I added a heater and power heads. The temperature fluctuated from low 60's to 88 degrees in the hottest part of summer. I could have added a fan on a timer to blow across the water from noon till 6:00 P.M. to keep it a bit cooler. After a few days of playing with the temperature and building a plastic covered wooden frame to keep the rain out, I added about 10 pieces of the nicest coralline encrusted rock I had - solid purple and pink! This would seed the aragonite rocks. The next day I went out to the garden to check on the coralline rock I had added and to my surprise they were all bleached except the under sides that were shaded. I didn't know what the problem was. I thought I was using the best lighting available, the sun of course. Still, what I didn't know was that coralline algae grow best in deep waters where the light isn't so bright compared with direct sunlight. I put powdered lime on the plastic cover like florists do to reduce light and keep it cooler. The still coralline hardly grew in this bright light.

In summary of the live rock kiddie pool experiment, I can say that the temperature fluctuation would have been more acceptable if I had used a 200-300 watt heater to keep the temperature above 70 at night and had used the fan on a timer or thermostat to keep it below 80 degrees in the day. Some temperature fluctuation like this is actually OK. I should have covered the wood frame over the pool with a blue tarp and a couple layers of florist's shade cloth to really cut down the sun light that I falsely believed was critically important at first. Two other alternatives would be to put the pool on the north side of the house to naturally cut the light intensity down. It would only receive blue sky light and be mostly shaded which would eliminate over heating. Or, I could have just set it up in my basement and used four 4 foot 40 watt flourescent lights which are very adequate for growing coraline algae. This would raise my electricity costs by only about $4-$5 a month. Just two 40 watt flourescents over a 55 or 75- gallon live rock propagation tank is fantastic for growing good coraline algae.

(Note: See the article on this web site on making live rock for even more up to date details on making live rock and growing coralline algae.)

Making live sand is even easier than live rock. The aragonite reef sand in the bottom of the pool tuned into live sand when bacteria and micro fauna multiplied and spread to it. You can just use oolitic sand or Reef Sand in the bottom of a new reef tank you are setting up and the life from the live rock will eventually spread to it, making it into live sand. Many people like to speed up the process by seeding the sand with some existing live sand from a store or from an established reef tank. By the way, I have successfully kept live sand and live coraline rock stored in open 5 gallon buckets in my basement for two months with no heaters at 55-60 degrees. No lights were used except what comes through the window. There was no apparent loss of bacteria, micro fauna or coraline algae. I did add fresh top off water every week or two.

It's about time to say good bye now. Get started on those coral cuttings, and maybe even a totally propagated (or mostly so) reef aquarium. Make at least some of the things yourself. I guess I can't expect everybody to tank raise their own fish! However, propagating corals, live rock and live sand isn't really so hard and can be a lot of fun. If you have questions or comments, you can write to me in care of Marine Fish Monthly. Include an SASE and phone number just in case. You can also E-mail me (surf's up!) at EZreef@yahoo.com. And remember: "A blenny raised is a blenny earned." Sea you next month.