The Staghorn Coral
May 19, 2009
These corals belong to the hard type and are much used in reef aquariums. Writing a text on them in general terms is the only way given the space available.
They are given their common name because, obviously enough, the branches of the coral generally resemble the horns of a stag, though the branches vary considerably. There are other common names such as tabletop coral and cat’s paw coral (some have flat tops as does a table so there are also those that resemble a cat’s paw), but these names do not fit so well overall and are not as widely used. The proper name for the type being looked at here is Acropora. I can immediately find 47 types of Acropora in the references available to me and I’m sure there are many more, one suggests a total of 300 or more. They each have their own proper name under the heading of Acropora, hence the general look only.
As a hard coral they belong in a reef aquarium of course. The aquarium should have powerful lighting such as metal halides, probably best supplemented by, say, two actinic fluorescent tubes. High seawater quality is a must, and the calcium and alkalinity levels need to be monitored. Acropora corals demand calcium and the amount of usage can be surprising in a well stocked reef, so supplementation from commercial sources could be possible in a small system, but it is likely to be too expensive and cumbersome for a medium or large one. In the latter the usual practice is to install a calcium reactor. The calcium level is best kept between 420ppm (parts per million) and 450ppm, though some aquarists elevate this to around 480ppm. Such a high level is not really necessary as long as the suggested lower levels are maintained. Alkalinity in an aquarium is best if it is higher than natural seawater levels. Alkalinity resists the tendency for pH to drop because of acidic action, in other words it acts as a buffer. The best level in an aquarium is between 3.5 meq/L and 4.5 meq/L. 4.0 meq/L seems reasonable. Some fluctuation doesn’t matter provided it is fairly minor. (NB. meq/L can be converted to dKH if desired, multiply by 2.8.)
So the corals need high quality seawater with appropriate calcium content and alkalinity, plus correct lighting. The lighting could have an effect on the coral’s colour; the colour could change from that when purchased. This change is usually because the symbiotic algae, the zooxanthellae, are reacting to the lighting available.
Another requirement is seawater movement. The majority of the corals are used to high seawater movement and this should be duplicated as far as possible. A minimum flow rate suggested by the guideline is twenty times the display aquarium net gallonage per hour, which is double that suggested for a soft coral display. This flow can be provided in the usual ways such as powerheads. It is worth considering the high output types with wide delivery nozzles as opposed to narrow nozzle types, particularly the ones that can be controlled and made to alternate seawater output level. Whatever type is chosen, they need to be positioned so that a jet of seawater is not directed straight at a coral, though this isn’t as important with wide nozzle types.
Not all Acropora corals require high seawater movement, though as said the majority available to the marine aquarist do. One way of generally judging seawater flow requirements is to consider the colouration, if it is bright then it is likely that intense light is required which brings the coral closer to the surface where strong movement prevails. Another indicator is the length and shape of the branches, if they are short and club like they resist high seawater movement better; longer and more slender branches are more likely to break. Generally, if there are any doubts place them in an area of high movement and, as with all introductions to the captive reef, observe to ensure all is well.
Acropora corals could worry the aquarist when they are first placed in the aquarium. Even though the conditions for them are excellent, they could take a while to settle before commencing to grow. Once they have settled however, and provided conditions are maintained, they shouldn’t be a problem.
When placing the corals allow room for growth, if conditions are good they are fast growers, some more than others and this growth can be such that the reef becomes overcrowded fairly quickly. Having said that, the corals are excellent for ‘fragging’, a term used in the marine hobby for culturing additional corals from a mother colony. This practice is excellent for the hobby and for the wild reef: for the hobby ‘fragged’ corals appear to be more resilient than those from the wild, for the wild reef if corals are ‘fragged’ not so many are required to be collected. Therefore if the captive reef does start to become overcrowded ‘fragging’ is a definite action to consider, and it isn’t difficult.
Though it varies, the branches of the corals are fairly fragile and snap easily, more so towards the tips. Therefore care is required when they are handled. Sometimes they can be positioned so that rocks hold them until they establish themselves, but it is probably better to secure them with some aquarium epoxy putty, which sets very quickly.
Acropora come in all sorts of shapes and colours. Most seem to be branched and resemble a terrestrial bush to some extent, with generally uniform branches sprouting out and upwards. These branches could, as said, be thick, short and club like or longer, dividing and slender. Others grow to a flat top shape thus the name ‘table coral’. The pink and blue of some types are, to me anyway, particularly lovely, though the colours vary with many others.
These corals are more demanding than most, but not all, of the soft corals and the aquarist has to be sure that he/she is willing to provide the ‘extras’ required – seawater should be top notch anyway, with very low nitrate and phosphate. The extras are controlled levels of calcium and alkalinity, high seawater movement and sufficiently powerful lighting. A stable environment is required as generally the corals tolerate changes poorly.
The link gives many pictures of the corals. Click on a picture to enlarge.
http://www.poppe-images.com/images/search_results.php?keyword_mh=Acropora&x=40&y=9
If the aquarist can provide the environment for the corals, the reward is a colourful and very ‘reefy’ display. A successful hard coral reef display is regarded by some as the pinnacle of achievement.
The Rose Anemone
May 1, 2009
One of the most intriguing sights within a marine aquarium is an anemone with a clownfish or two. The clown fish on its own, particularly certain types such as the common clown fish (Amphiprion ocellaris), could be the flag for marines. Seeing a clownfish dwelling among the stinging tentacles of an anemone adds to it. It should be mentioned that clownfish have anemone preferences, and a check should be made if a clownfish is to be offered an anemone as home.
While in cautionary mode, it should be noted that anemones are not for novices, it is necessary that experience is gained first, experience in maintaining high quality seawater and equally high quality general habitat. In addition, anemones such as the one looked at here require correct lighting, in the same way that most commonly kept corals do. This is because of the presence of zooxanthellae, single celled symbiotic algae within the flesh. The zooxanthellae give the anemone its colours.
The Rose Anemone is properly called Entacmaea quadricolor. Looking at the proper name it is clear why it is also commonly known as the four coloured anemone. It can also be recognized as a short part of the tentacles are bulbous, this occurs towards the ends. Remembering that some clownfish refuse for some reason to take up home in an anemone even though it is of the correct type, the Rose Anemone should be acceptable to Amphiprion bicinctus, A. clarki, A. ephippium, and A. frenatus. That’s quite a choice, but as said there’s no guarantee.
Some symbiotic anemones will anchor themselves in the substrata which can sometimes present a positioning problem for the aquarist. The Rose Anemone however doesn’t require substrata, it is happy on rocks. Well, that isn’t completely correct, it is happy between rocks in a fairly deep cleft, which is best smooth, meaning smooth sides and bottom. The anemone is able to contract considerably into the cleft if threatened. They should not be in the direct flow from any powerhead or the like, the seawater flow is preferred to be gentle. In a reef system positioning would need some thought because of the high seawater flow, and at the same time remembering the anemone’s light requirements.
Having mentioned the anemone’s preferences, it would seem that this particular one is fussy. However, it is reported to be one of the easiest, or perhaps the easiest anemone to keep among the symbiotic types (symbiotic = anemone/clownfish).
There is one potential habit with this anemone that some aquarists face and others not – it can without apparent reason go wandering. Even though the anemone has been provided with all necessary requirements to settle, it could go for a walk which is not going to necessarily please the aquarist. It could end up a very short distance away from where it was placed, or it could end up down the back of rocks hardly on view and the like. Or it could stay exactly where put!
If the anemone does move to a position unacceptable to the aquarist it could be transferred to a new area which again is designed to meet all its needs. Care has to be taken, as the anemone could well be well fastened to a rock and clumsy attempts to release it could cause damage and affect its health. If at all possible, if the anemone is fastened to a rock, the rock should be moved to a new area with the anemone and be used in the construction of the new cleft. With a prayer for good luck maybe the anemone will stay put.
Feeding the anemone is easy, all that is required is a smallish piece of mussel, lancefish or the like. Once or twice a week the food is placed on the tentacles, and the anemone will transport it to the mouth. If a clownfish is present it is possible that the food will become of immediate interest and it may not reach the mouth, so this needs to be watched for.
The anemone could reach a diameter of 20 inches (circa 50.75 cm) though this is unlikely in an aquarium. Having said that, I once kept a symbiotic anemone of a different type that grew so large it had to go back to the local fish shop. Sadly, the clownfish also went with it.
As said, symbiotic anemones are not for the inexperienced. If including one in the display is being considered, then this one is reported to be a little ‘easier’. Watch out for walkabouts though!
The link provides some pictures.
http://www.poppe-images.com/images/search_results.php?keyword_mh=Entacmaea+quadricolor&x=54&y=12
The Coral Reef
April 30, 2009
For the most part marine aquarists are interested in the wild coral reefs. These reefs offer a diversity of life that challenges, or perhaps exceeds, the rainforests.
Very many corals are now being propagated and fish, once thought impossible to breed are also being bred in increasing numbers of species. These actions are occurring with home aquarists and commercial organizations, a great benefit to aquarists and the wild reefs.
The problem that sometimes arises with reading material about the wild coral reefs that goes into any depth is that the material becomes entangled with science. Unless the reader is a scientist then interest is rapidly lost in the material. What is wanted is something beyond a hobby book that advises ‘how to’, though these are of course very important themselves (how many fish and corals are lost because the habitat when initially created was below standard?). The information should advise on what happens on a coral reef, habits and instincts, reproduction, in fact anything that is relevant to a layman, and all the better if the material permits the aquarist to choose the subject that is of interest and ignore any other.
There isn’t a requirement to be a scientist to achieve a successful reef or fish only aquarium, there is only a need to have a basic understanding of what is needed to properly support the life that is to be kept. Beyond this, each aquarist as an individual has more general interest or not.
Here’s a website that gives general information on wild coral reefs covering most of the areas that an aquarist could be interested in. It is written in a straightforward way and not bogged down scientifically, if I can put it that way.
http://www.seaworld.org/animal-info/info-books/coral/index.htm
How To Cut Your Coral
April 26, 2009
It’s enough to make an aquarist shudder, a beautiful reef with corals that are healthy and expanded, fancy cutting one? Er, not really, no.
The fact is that corals that are healthy are going to grow. Growth is of course absolutely normal and occurs with whatever the type of coral, soft or hard, and whatever species it is.
A captive coral reef that is successful will need attention in time, in addition to the usual but very important routine maintenance. Growth of corals can change seawater flow, reducing it for some corals which is not good. Corals that are becoming large can also overshadow others, which mean the corals in shadow are going to suffer because the zooxanthellae object to the lack of light. Corals can also expand to the point where they touch and in some cases this is when a territorial war begins.
The aquarist can deal with all of this without spoiling the appearance of the reef. The corals that are now becoming too large can be cut. The hobby term for cutting corals is ‘fragging’.
If it is only one coral or just a few that are causing problems, cutting can be done and the cuttings, or ‘frags’, can be grown on in the display aquarium. Or the aquarist could use a small shallow additional aquarium to grow on more numerous frags.
The frags when available and known to be healthy could be used as exchanges with other aquarists, or taken to the LFS for a credit or merchandise.
Frags are generally more tolerant of aquarium conditions than their wild reef counterparts, and this is a definite plus for the marine aquarist.
Propagating corals is not difficult and the procedures are straightforward. Corals are tolerant of the procedure and seldom suffer any negative side effects. Propagation is also becoming more important as time passes and the wild reefs slip into more serious trouble.
The link is a website that is very well respected. On arrival, a list will be seen on the left hand side. There are two headings to click on relevant to propagation, the first near the top of the list called ‘The Frugal Reefer’ and the second further down called ‘Propagation’. There are sub-headings to choose from.
The website is very interesting overall so it is worthwhile having a general look arounds well.
http://www.garf.org/index.shtml
Sea Hares
April 20, 2009
Many reef aquarists who have some experience in maintaining their aquariums that is maintaining seawater quality at a high level are constantly on the lookout for something that could fall into the category of ‘unusual’.
The life form that is found – if found – has to meet certain criteria in the aquarist’s mind before it receives the sea of approval. First and foremost, it has to be reef safe, in other words it must not start eating the aquarist’s coral collection! Second, it has to contribute something to the reef, this contribution could be beauty, or shape, or a combination. Or it could be just weird.
A life form that is not only interesting, could probably be called beautiful, and in addition is useful to the aquarist is the sea hare. These are often termed ‘slugs’ but this is a little unfair, as the word ‘slug’ could initiate thoughts of the gardening problem slug which eats if it has the chance much of the garden plants. Sea hares don’t deserve this kind of press. They will actively consume algae in the aquarium. The aquarist with a green hair algae problem would no doubt be delighted, but it is possible the creatures would also find decorative algae a pleasant food.
Sea hares are sometimes obtainable from the local fish shop, or if not can usually be found for sale wider afield. They are also being commercially bred too, which is a great boon. Its wonderful how many sea creatures, on a lengthening list, are now being bred.
The aquarist if intending to buy one of these creatures has to show some caution, but no more than when buying a fish. It is important to know the species that is being obtained; this information should be readily obtainable from the seller. If it isn’t, then don’t buy.
Why should caution be necessary? When buying a fish it is necessary to know the species so that the eventual size is known. Many fish are small when at the dealers but grow quite rapidly if nature intended them to do so.
Similarly, sea hares have different sizes. For example, one type which is of no interest to the aquarist is reported to grow to 39.5 inches (circa 100 cm), just a bit large for our aquariums! Another, the spotted sea hare (Aplysia californica) could grow to about 15 inches (circa 38 cm). Another much smaller species commonly called the green sea hare (Phyllaplysia taylori) could grow to between ¾ inch (circa 2 cm) and 3 inches (circa 7.5 cm). The spotted sea hare will usually eat good quantities of algae, the preference being for green. The corals that that the sea hare is living with need to be fairly robust and well anchored, particularly as the hare’s size increases. The smaller hare is not such an easy feeder, as it lives in sea grass ‘fields’, the sea grass is its reported food. They are reported to eat algae but this could prove to be inadequate. Also, predators in the aquarium could take an unhealthy interest in the creature.
Sea hares do not have any particular demands apart from the usual one of good seawater quality. If the aquarist is cautious in purchase and is able to provide the food required, then the aquarium will be enriched with a creature that some would call beautiful, others different, and others weird.
There is one link provided and a video. The link is to an advanced website, but this should not put any reader off as the text is straightforward. Just scroll down until the sections that are of interest are found. The video shows a sea hare in an aquarium. Note the camouflage.
http://www.advancedaquarist.com/issues/oct2004/invert.htm
Clams
April 19, 2009
Those who keep a mixed reef or corals only type are the only aquarists who would be interested in clams, or at least in the clams that are being looked at here, which are in the family Tridacnidae. This includes some of the giant species from which stories of divers being trapped have been born, the stories no doubt being unsupported by fact. Not all of them have the potential to be giants, there are those that are much more aquarium sized.
The link shows some of these clams: http://www.poppe-images.com/images/search_results.php?keyword_mh=tridacna&x=73&y=11
Even if the aquarium system owned is a reef the successful keeping of these clams depends on adequate lighting, for within the flesh are zooxanthellae, the same single celled algae that reside within the flesh of most of the corals commonly kept. All reef aquariums do not have the required lighting, some use banks of fluorescent tubes. Unless the clam placement is very high on the reef this light is likely to be inadequate, and even if placed high the light could be insufficient. Insufficient light will prove to be fatal, and the sign for this is a brown coloured mantle. Once this has occurred then the clam is normally doomed and placing it under intense light in the hope of saving it is likely to fail. The best lighting for clams is properly powered (that is sufficient wattage) metal halide which can penetrate the seawater reasonably.
Placing a clam high on the reef in the hope of sufficient light has a downside in addition to the possibility there still won’t be enough light. This downside is seawater movement as the clams prefer this to be very moderate to weak. The seawater movement in an SPS reef is high and a soft coral reef is more than the preference of the clams. So at least an area where the clam is protected from high movement is required. In adequately lit aquariums (adequately meaning the lighting has sufficient power to penetrate sufficiently to the bottom) the clams should do well placed low down on the sand.
Despite the absolute necessity for adequate light the clams are easy in one respect and that is feeding. They are filter feeders, but the products of their zooxanthellae are sufficient to meet their requirements, which mean that the aquarist doesn’t need to worry about additional feeding. Any food that is placed in the aquarium that is suitable for filter feeders is likely to be useful to the clams as well.
There are three clams that are probably most of interest to the reef aquarist, and these are Tridacna crocea which grows to about 5 inches (circa 12.5 cm), Tridacna gigas which could grow to about 50 inches (circa 127 cm), and Tridacna maxima which could grow to about 14 inches (circa 35.5 cm). It would seem that the only two suitable to the aquarist are Tridacna crocea and Tridacna maxima, but all three are obtainable if searched for. If Tridacna gigas begins to become too large it could be moved very carefully to more suitable accommodation. It takes a long time to reach a large size.
The attraction for aquarists with these clams is their beautifully marked mantles. When healthy and fully open they are extremely attractive and automatically draw the eye.
If the aquarist has suitable accommodation, that is a reef aquarium with suitably powerful lighting, and also some experience has been gained the purchase of these clams is a very worthwhile consideration. (Experience means that high quality seawater can be maintained and the aquarist has an understanding of aquarium husbandry). They provide a very ‘reefy’ looking life form for the captive reef and one that has gorgeous colours when open. In addition feeding is not a problem so seawater quality will not be potentially downgraded.
Tridacna clams are now being commercially produced and if at all possible these should be the ones purchased, even though their size may be fairly small.
Aquarists And The Declining Reefs
March 30, 2009
There is little argument nowadays over whether or not there is any decline in the health of wild coral reefs. The discussion now seems to be more about the speed of decline. Some reefs remain relatively fine, but others are getting into a sorry state.
Scientists tell us about the acidification, or reduction in pH, of the seas and oceans caused by carbon dioxide in the atmosphere. They also advise of the slow increase in temperature. Both of these, in the long term at least, are going to cause trouble we are advised.
Imported into the US and Europe are huge numbers of marine fish and invertebrates destined for the marine hobby. They are distributed all over these areas for purchase by hobbyists. Does the import of this reef life accelerate the decline in the reefs? I cannot completely answer that question as I don’t have sufficient facts – but at a considered guess I would say ‘no’.
First of all what of collection from the reefs? Huge strides have been made over the last decade in the correction of unwanted collection practices. Once collectors realized that their future jobs were at stake and subject to there being something to collect, they listened. Though there are still problems that have not been cleared in some areas, collection of fish for example is by net and not cyanide. Holding facilities are much improved. Distribution methods – packaging mainly – has been much improved.
In addition to better collection methods, in the reef areas something is being done about the removal of corals. Collectors are now, though not in all areas, propagating them. They are sometimes laid out on vast undersea trays like seedlings in a gardening nursery. As they mature, they are sold on. Each one that matures is one less taken from the reef.
When the packaged livestock reaches its destination, usually wholesale shops and then retail ones, it is handled in a better way. Though there are some distributors and shops that are poor in their handling practices, most are fine. The packages are opened in dimmed or red light and the livestock permitted time to adjust. This is good, and after all it is in the wholesalers and retailers interest to operate good practices and protect the stock which represents their livelihood.
What of aquarists? Are we guilty of anything? There are those in the hobby who should not be called aquarists. They are a minority fortunately. These are the ones who find a fish dead and go and get another without thought as to why or how it died. Just replace it, doesn’t matter! Of course it does matter, whether it is a coral, a fish or whatever. Fortunately the majority of aquarists can rightly call themselves that. From keen novice to very advanced they care for the livestock properly and maintain a high quality environment for them. Is that enough though?
The first thing is that this hobby is for enjoyment, there isn’t any arguing with that, and there’s nothing wrong with it either. The majority of aquarists maintain their aquariums properly – perhaps I could even say respect their aquariums – and enjoy the hobby immensely. Looking at a good marine aquarium it isn’t difficult to see where the enjoyment comes from. The first requirement to protect the wild reef is to care for captive livestock well. Then more will not be needed to replace it, unless the fish or whatever has reached the end of its allotted time.
Many aquarists, once they have gained experience in successful aquarium husbandry, decide to have a go at propagating easy corals, or easy to start with anyway. This decision may be caused simply because a coral or more have become too large and need reducing in size. The parts removed can be grown into new corals and once the aquarist has taken the plunge it is surprising how easy it actually is. The common name for propagation in the hobby is ‘fragging’. This practice can only be good, as the produced new corals can be taken to the LFS or given to an aquarist friend. This means that the demand for corals has reduced by that much, little as it may be.
Other aquarists go into propagation in a bigger way, by having a shallow dedicated tank for the task. This has a higher impact of course and at the same time could be helping to meet the running cost of the aquarist’s aquarium.
Commercial propagation is becoming more known and with far more facilities this has a big impact on imports and thus the wild reef.
It is not only corals that are being propagated by aquarists and commercial interests, fish are also being bred. It wasn’t that long ago that it was thought that breeding marine fish would be nearly impossible. The belief was based on the simple fact that the fish come from a reef situated in the immensity of the sea or ocean. However, more and more fish are appearing that have never seen a wild reef.
There is another plus with this propagation and breeding. This is that the fish and corals that have only ever had an aquarium for a home appear tougher – more resilient – than their wild counterparts.
As expertise within the hobby and commercially increases, so will the availability of livestock from these sources. At the same time the demand on the wild reefs will reduce. There will always be a demand on the wild reefs as it is quite probable that not all livestock is amenable to commercial and home production. In addition, as more and more propagation and breeding occurs there will effectively be a ‘bank’ for the livestock involved, as the knowledge of ‘how to’ once gained will not be lost.
The advance in knowledge by home aquarists sometimes surprises scientists, and many scientists do not dismiss aquarists as ‘amateur fiddlers’ any more. For example there are many scientists – those qualified in the scientific discipline of marine study – who regularly write for hobby magazines. Another example is taken from the book ‘Aquarium Corals’ by Eric H. Borneman. It is the foreword, written by Dr. J. E. N. Veron, who writes… ‘Just as comets are now being discovered by amateur star-watches rather than by professional astronomers, aquarists are now moving into an area of knowledge that was once the exclusive domain of marine biologists’. Of course this doesn’t apply to all of us but nevertheless demonstrates that aquarists are being noticed, and quite rightly so. Aquarists have hands on experience of salt water life.
No-one is going to try and state that all is right within the hobby and the commercial marine world. It isn’t, there are idiots. The majority however are not, they are careful in the choice of livestock and in its maintenance.
I have a positive view of the position of the hobby in relation to the wild reef. We aquarists are not causing Mother Nature much trouble; we are, albeit indirectly, assisting her. As time passes, this assistance will increase. Livestock imports from the wild reefs need to be sensible and at the same time causes of destructive pollution tackled. The wild reefs are truly wondrous natural areas and deserve our respect.
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