Trimming A Branching Soft Coral

If the marine environment is of high quality then the occupants should do well. This includes the growth of corals which of course is good. However, this in itself can demand attention from the aquarist.

Some soft branching corals can show very significant growth.This could interfere with seawater flow and light availability – other corals could suffer because of it. A large branch over a smallish coral, throwing it into shade, could mean problems for that coral if the aquarist let things be.

So what can be done? It’s a little worrying when the question of cutting a coral arises and the thought ‘What if?’ comes to mind. The fact is that provided the environment is good corals repond well to trimming. The trimming shouldn’t be too severe of course and thought needs to be given to where and how. The where is easy, it’s the offending branch. The how is also easy, just some care is required.

All that is required in the way of equipment is a pair of quite long and definitely sharp scissors and a bowl to put the cut off coral in. A sharp knife of good length could also be used but scissors tend to permit more accuracy generally.

It’s not time for cutting just yet. First, the cut point should be made where the coral will not be left looking out of balance, that is, it should still look normal when the branch is removed. Usually the cut is made near to the main stem and a very small distance away from it.

Once the cut point has been decided and before the coral shrinks because of interference from the aquarist, the size of the cut off branch should be noted. Is there anywhere in the aquarium that it could be relocated? If there is then it can be securely placed between rocks. If not, then the plastic bowl will hold the piece until it can be transported to the dealers (speak to them first) or passed on to another aquarist. Before being transported in a plastic bag the cut off coral can be placed in seawater in the bowl and the bowl floated in the aquarium to maintain temperature.

The time has come for the cut to be made. Before approaching the coral the aquarist should note the angle the scissors will need to be at. Hands into the aquarium and with the scissors placed as required a single cut right across the base of the the branch should be made – do not open and shut the scissors as would be done when cutting a length of cloth, what is needed is a straight neat cut without any hacking. The branch should come away completely. Sometimes the branch is still fixed to the stem by a shred of coral – cut this also in one movement. The cut branch should never be pulled off by shearing any attachment by force.

The coral will of course react, quite understandably really! It will shrink and go into ‘sulk’ mode. It could also eject some milky substance into the seawater, this is a result of deflation and usually not a concern. The coral will remain closed up for a day or so but will inflate again. The coral should be watched for any sign of rot around the cutting site, this is unlikely if the job has been neatly done. If any rot does occur then it should be removed with about 1/4″ of the cut into healthy coral. For cuts of this type a very sharp knife is generally best.

The photo at the head of this text shows a coral two days after being trimmed. In the photo below the branch on the left of the coral is re-growth from a similar trimming operation which occurred about five months earlier.

Generally speaking corals have a high capacity to re-grow. The re-growth is likely to be different from the original, and where one branch has been removed for example two could re-grow, each of a smaller diameter or just one again. Corals can be trimmed time and again and provided the trimming is not too severe there will usually not be a problem.

Trimming corals has the advantage that additional corals are being produced for use by the aquarist, other aquarists or for the dealer. This is good for the hobby and the reefs. An aquarist who designs a reef carefully could fully populate it over time by using additional corals, although this is not so good an option from the point of view of captive reef variety.

Maintaining an established reef is simple overall - provide a high quality environment, properly populate and take necessary actions following observation, such as the one described here.

What Is An Invertebrate?

To avoid becoming a squishy heap on the ground humans have a skeleton. Quite a good invention really, not having a skeleton would cause quite a few difficult problems.

Humans aren’t alone with the possession of a skeleton of course; there are all sorts of life forms that have one too, how about the elephant or man’s best friend the dog as just two examples.

Skeletons are not essential to life however; there are creatures that don’t use one at all. As a non-scientist I can say that they use a different method to maintain their body shape, I’m not sure how a scientist would put it. For example a shrimp has a hard outer shell rather than an inner skeleton.

Vertebrates, those that have a skeleton, are vastly outnumbered in the world. It is estimated that vertebrates are around 3% of the life forms in the world. It follows that a massive 97% (I just had to demonstrate my mathematical abilities) are invertebrates.

There are land dwelling insects such as spiders and worms, examples of well known invertebrates. In the cold sea there are huge numbers of plankton, anemones, sponges etc. The warm seas contain many better known (to the marine aquarist) invertebrate species, including filter feeding worms, shrimps, corals and sometimes very large anemones. It is with some anemones of course that the representatives of the vertebrate/invertebrate world have combined forces to mutual advantage; these are the clown fish with their selected hosts. There are other examples of this life style.

Invertebrates are very adaptable as demonstrated by the discovery of volcanic activity deep in the sea well beyond the sun’s light. Scientists used to accept that life basically depends on the availability of light from the sun, an example of which is that plant life uses the sun’s light to photosynthesize and grow, and then the plant life is eaten by a herbivore from which energy is obtained. Herbivores are then the prey for carnivores. They all basically depend on the plants and the sun. This belief has been changed by the life found near this deep volcanic activity, including filter feeding worms, mollusks, bacteria and crabs which depend not on the sun’s light but on heat and chemicals.*

Anyway marine aquarists, or rather those who maintain a reef system, keep various types of invertebrate including shrimps, corals, sponges, anemones, filter feeding worms etc. These very interesting life forms only ask for a few things for success, including high quality seawater, for the majority of corals and some others sufficient light of the correct spectrum, space to grow and freedom from predation. It is usually important to place for example corals in a position where they receive sufficient seawater flow.

It is worthwhile noting that all marine aquariums, big or small, fish only or reef, depend on invertebrates for their health and life. The bio-filtration system, whether this is live rock or canister filters, contains bacteria that deal with the toxins ammonia and nitrite. Without these bacteria the life in the aquarium would die. With live rock, further bacteria should be able to deal with the sometimes troublesome nitrate.

Those aquarists who make use of natural live rock could discover that they have invertebrate life forms in their aquariums that they didn’t import themselves or at least not intentionally. Some such as filter feeding worms could be welcome. Others such as the Aiptasia anemone are not welcome. The Mantis shrimp is another, though in this case it is worth keeping but needs re-housing to an area where problems won’t arise.

Invertebrates provide the aquarist with a chance to create a living reef at home, be this large or small, though compared to Mother Nature’s creations all home reefs are miniscule. Nevertheless, a successful home reef is wonderful to see.

(* Reference: Marine Invertebrates. Martyn Haywood & Sue Wells)

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Enough Light? Must Be

Watching a marine aquarium is a great pleasure and probably one of the major reasons why so many keep them. With a reef system sometimes a new arrival is seen to appear, or a species of coral that is already present appears somewhere else.

On a few occasions I’ve noticed arrivals that must have come in with coral rock, such as a very dark and tiny crab that was very timid and only appeared at ‘dusk’. Its presence was shown by an exploratory claw appearing out of a crevice. The crab hasn’t been seen for a long time and no doubt has gone.

Corals too can appear when new live or coral rock is introduced. In this case the coral type is already present in the aquarium with a fairly large colony, and the new appearance is in a completely separate part of the aquarium.

As far as I can tell, the main colony is a Rhodactis species (the purchase was made years ago and the dealer didn’t have a clue). Rhodactis are also commonly known as hairy mushrooms and mushroom anemones. I think it could possibly be Rhodactis indosinensis – but is this correct as most grow larger than my specimens? Maybe they are Discosoma species. The colony is receiving plenty of light as it is half way up the reef (about half way up the aquarium depth). The new one, however, is not; it is right down at the bottom. The aquarium is 24″ deep (21.5″ from lights to coral). Further, this new growth is at the end of the aquarium and is partly shadowed by another coral.

Is my lighting system powerful? No is the answer, it’s a fluorescent array of five tubes, three marine whites and two marine blues (actinic). They’re not even T5’s, they’re T8’s. The reef is furnished with soft corals and they are perfectly happy but I had to wonder at the growth of this new one. The blues will penetrate well but even so….

The original colony is in an ideal spot apart from seawater flow which is a bit too vigorous, they prefer weak flow. However, I’ve left things as they are as the mushrooms are clearly healthy and open well, though not to as large an extent as with lower seawater flow.

The new one is the reverse; it’s in an area of slow flow. However, as said, I wondered about the light. It has been slowly growing for about 8 months now and has reached a size of 3″ across, which, because of the slow seawater flow, is full expansion. However, though I believed the slow growth must be because of light, or at least the lack of it, it seems this could be wrong. Looking at one of the references available to me * it seems that though light is no doubt an influencing factor it isn’t that important, as strong lighting is not required by Rhodactis species though they will tolerate it. Discosoma species prefer in many cases reduced light.

How did the new growth appear? It is possible it’s by natural detachment, but in this case is more likely to be my error. From time to time I have to get out the trusty and sharp scissors and reduce the colony to prevent interference with other species. Part of this is catching the detached parts. These corals are easy to ‘frag’ so if a small part escaped my attention and lodged it is more than likely to grow.

So there we are – what started as a general belief followed up by some simple research has turned my notion upside down. Goes to show how important basic research is. As far as identifying the species, I’d need a marine biologist and I bet there’d be uncertainty even then.

(*Reference: Aquarium Corals. Eric H. Borneman)

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Reef Loss – Some Very Worrying Information!

It seems to me that if captive reef aquarists love their corals it follows that they love the wild coral reefs. Surely so, it’s where the corals, for the most part, came from.

We all know of the threat of global warming – no, don’t switch off, there isn’t yet another lecture coming. As far as coral reefs are concerned the potential increase in sea temperature is a threat to corals. In addition, because the seas are absorbing more carbon dioxide acidification is occurring (acidification means that the pH of the seawater is reducing), which is another threat to corals. If corals are threatened then it is said that fish species or many of them are also threatened.

It underlines the need to treat all imported corals and fish properly and to attempt to cultivate and breed them wherever possible. I’ve said before that along with public aquariums the thousands of home aquariums around the world could become a coral reef ‘seed bank’.

I’m not a scientist but most scientists are agreed on the truth of the global warming threat. When a respected scientist speaks who has a name reasonably well known to aquarists it carries more authority within the hobby. The name is Dr J. Veron (known generally as Charlie for some reason). Owners of the book ‘Aquarium Corals’ by Eric H. Borneman will recognize the name, as the foreword in that book is by him.

The point is that the probable future of wild coral reefs including the Great Barrier Reef has been made available on ‘The Times’ website (‘The Times’ is a highly respected UK newspaper).

The link is to that website and should make interesting but worrying reading for all. Click on the ‘Related Links’ and ‘Coral Bleaching Graphic’ as well (boxed on left-hand side of page), they’re interesting.

http://www.timesonline.co.uk/tol/news/environment/article6652866.ece   

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Things Change

Pretty obvious really! The weather is an example. But no, we’re concerned with marine aquariums of course.

In a fish only aquarium the changes are usually, strangely enough, to do with fish. New additions, growth, the cave/hole they live in and the like. In a reef system more changes are often noticeable.

On the wild reef changes occur slowly for the most part, though things could happen quickly. If a storm comes along then coral formation could change as corals are broken. Unfortunately change can also happen quickly (in terms of the life of the reef) caused by man-made pollution and interference. Normal reef changes are when one coral slowly dominates another in a long drawn out battle for space, or coral colonies spread over new areas.

So change is quite natural. In the aquarium changes could be unnatural, that is caused by the aquarist. An example is the cutting of corals because of growth. When corals grow they could shadow or at least reduce the light available for others and in addition the seawater flow could be altered, meaning that some corals do not receive the flow they require. So the aquarist cuts the corals to maintain the balance of light and/or flow. This is a quite drastic change that doesn’t occur in the wild of course. Overshadowing will occur to some extent though. Hopefully the aquarist having cut corals will ‘frag’ them so that additional good comes from the exercise.

Other changes can occur and this unfortunately includes coral failure. Nowadays with the greater amount of knowledge available failure in this area should be much reduced. However, failure can occur in more than the usual way, the usual way being that a coral is just not happy, closes and shrinks away quite rapidly.

In my soft coral reef there is a colony of green star polyps, which are sometimes called star polyps or daisy polyps. The proper name is Pachyclavularia purpurea (some call it Clavularia viridis but this is incorrect)*. Anyway, the thing is that this colony arrived six years ago on a rock which was completely covered. The rock would be generally about 6 inches across at the base and about 4 inches high. After a while the coral spread onto a neighbouring rock and completely covered that as well. There wasn’t anywhere else for it to go so it stopped spreading.

For a long while it just came out at ‘dawn’ and went in at ‘dusk’. It was perfectly healthy and also completely at home, happy with the lighting and seawater currents. It was attractive and added to the many colours of the display.

Eventually I noted that it was beginning to climb onto itself that is it had nowhere to go except to cover itself. So the mat was spreading and new polyps were opening on top of the original.

I was quite concerned about this as I thought first of all that the lower layer could lose adhesion – but it didn’t. The spread across a lower layer continued for a long while, years in fact and eventually the colony was higher than it had been originally because of the layering. I was pleased in a way as the shape of the colony had altered; it no longer followed the shape of the rock but had formed mounds and spires plus some flatter surfaces, making it more interesting.

This situation continued until I noticed that some of the colony, a small area only, didn’t have any extended polyps. Sometimes the colony had not expanded for a whole day or so on previous occasions, therefore I wasn’t concerned.

However, the polyp areas that failed to expand extended in area. Eventually I noticed a bare area of rock down near the base. This area extended until very nearly all of the rock was bare. Some of the remaining un-layered matt containing polyps was removed and placed elsewhere in the aquarium and this is opening normally, appearing to be beginning to form a new colony.

Apart from one area on the adjacent rock that was colonized there wasn’t anything left. The reduction and loss happened over about a period of two months, which isn’t very long.

It isn’t all bad news though. I’ve recently noticed that a few odd polyps have appeared on the rock and hopefully these will lead to a re-colonization. If this occurs then I’ll recover the original colony and have an additional transplanted one.

So why did this occur? All other corals are fine, expanded with proper polyp extension. It follows that seawater quality and lighting are also as they should be.

I reckon my original fear that the original matt could lose adhesion was not the reason for the die-back. Adhesion loss could of course have occurred but the colony remained in place.

It seems to me that as the colony for the most part actually disappeared then it must have ‘dissolved’, or rotted away. This could have started with the covered lower layers rotting, which would have caused the top layer to become affected.

What I have to do now is wait and continue observing the polyps that remain, both the two small colonies and the separate polyps. Hopefully the original colony will grow back to full size.

If full size is achieved then perhaps the colony will eventually begin to overgrow itself. This would presumably mean the colony will eventually fail again. The possible way out of this is to put a bare rock alongside the re-generated colony which can be grown over. This can be placed elsewhere in the reef or given away.

As in the wild changes occur with the captive reef. It all makes the hobby so interesting, don’t you think?

The photos (taken by me so not of professional standard!) show the area where the original colony existed alongside the rock that was colonized, where some of the coral remains. The other photo, taken closer in, shows the polyps that have appeared that give me hope that a new colony will re-generate.

(*Reference: Aquarium Corals. Eric H. Borneham)

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The Bubble Coral

This coral adds to all the differing shapes and colours of corals that could be added to the reef aquarium. It belongs to the stony or hard coral type.

Besides bubble coral other common names are octocoral, bladder and grape coral. The proper name is Plerogyra sinuosa. It is not difficult to obtain and if seen in a store is easily recognized, as the name implies it is covered in inflated fairly large bubbles (or bladders or grapes). On sight the coral appears to be delicate but they are fairly tough. Nevertheless, handling and placement need some care.

The coral is often roundish with the bubbles emerging from the upper surfaces. The bubbles are inflated and it is reported could expand up to around 500%, leaving the wall of the bubble the thickness of one zooxanthellae.* Quite thin then!

The coral is expanded during daylight hours. At night the bubbles retract and tentacles appear which are used for feeding.

As already said some care is needed with handling and placement. Though the coral is tougher than it looks, handling should be minimized (as with all corals) and the chosen place on the reef should not be close to sharp pointed or edged rocks in case of damage to the coral, the bubbles could rub against the adjacent rocks in seawater currents. Ensure the coral is secure; a fall could damage it and lead to infection. The coral can be placed nearly anywhere on the reef as it does not require powerful lighting, however strong lighting does not appear to cause any trouble once acclimatized. A newly purchased coral should not be immediately exposed to very powerful light as they may have been used to low light in the wild and the stronger light could shock and damage it, so it is best to keep overly powerful light off the coral anyway. Reef quality lighting (spectrum) is required because of the zooxanthellae, it could be possible that the size of the bubbles is controlled by it, the lower the lighting strength the larger the bubbles to ensure there is enough light. What does mainly limit potential position is the strength of the seawater current, this should not be strong or the bubbles will be too violently shaken or will not expand to their fullest. The best seawater current strength is low to moderate. A final point on placement – it is capable of extending quite potent sweeper tentacles which could attack and damage adjacent corals, so maintain a good space between it and any neighbours. This is good practice with corals anyway.

The coral is not overly striking in colour as some are; though the colours vary they are not bright. This is not to say the coral is not attractive, it certainly is. It could be green, ivory, cream or white and some have bubbles that have clear colourless narrow stripes on them.

This coral does not present any feeding problems; there isn’t any need for suspension feeding. A small piece of de-frosted fish or similar can be gently placed on the coral and will be taken in, what could be easier? The coral is easy to feed and sometimes is overfed because of it. One feeding every other day, or longer intervals according to experience should suffice.

The bubble coral should not present any difficulty even to a moderately experienced aquarist, provided that seawater quality is high and attention is given to proper placement on the reef with regard to seawater current strength, security and lighting. The coral is yet another variation that Mother Nature has evolved which can be an attractive and interesting addition to a reef aquarium.

(*Reference: Aquarium Corals. Eric H. Borneman)

The first link is to photographs, click on it to enlarge. The second is a short video.

http://www.poppe-images.com/images/search_results.php?keyword_mh=Plerogyra+sinuosa&x=53&y=8

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The Pulse Coral

The pulse coral belongs to the soft corals and is well known. It is often seen in local fish shops and though often at a higher price than many other soft corals, is not out of the reach of most aquarists.

These corals are attractive in general, but the main attraction is the pulsing of the polyps, they rhythmically open and close. There has been considerable argument over why this should be, and the most obvious answer held sway for quite a long time. This answer was that by pulsing the coral drew suspended food particles to it so that they could be captured. Watching the coral’s action this seems reasonable. However, the latest thinking that I am aware of is that the pulsing is to obtain more oxygen, in other words a breathing movement, more seawater is passed across the polyps thus more oxygen becomes available. Some aquarists automatically dismiss this as it is compared to the similarity of human breathing. Several authorities support the ‘breathing’ reason. I am not able to state the scientifically proven correct answer. Perhaps there will be scientific enquiry into the coral and facts will emerge. If they already have I’d be pleased to know.

Anyway, the attractive coral is upgraded to fascinating by the pulsing of the polyps. Sometimes in an aquarium the polyps cease to pulse, or only pulse weakly. Again, at least to me a definitive answer as to why this should be is not known. There has been argument, some saying that in an aquarium iodine is likely to be lacking and this causes it. However, some have measured for iodine and found it present at a correct level yet there isn’t any pulsing. Others have suggested that the aquarium may have saturation levels of oxygen and there isn’t a need for pulsing. The latter one could have some merit if the coral’s reason for pulsing is related to oxygen. (The respiration reason for pulsing is cited in some respected books.) Another reason suggested is that there is excessive nitrate in the seawater. If the polyps reduce their pulsing action nitrate is easily checked for, but unfortunately there doesn’t seem to have been any feedback from aquarists on this point (to my knowledge).  Again perhaps science will come to our aid one day. The good thing is that even if the pulsing does reduce or cease, the coral does not seem to decline and remains attractive.

Pulse coral is the major common name, Xenia elongata or Xenia umbellata the proper ones (two separate types). There are other pulsing corals. They are suitable of course for a reef aquarium. The coral has a thick ‘trunk’ which leads to many ‘branches’, which in turn split off and lead to many polyps. The coral attaches to rock. It is important that the coral receives sufficient light as the flesh contains zooxanthellae which supply the majority of the coral’s food requirements. Ensure the light reaching the coral is direct and bright. Seawater movement should be moderate. Excessive seawater movement will have a detrimental effect.

The pulse corals are not difficult to keep and do well in an aquarium, provided of course that seawater quality is high and lighting is adequate. Placement seems to be one key to success (as with many other types), this could be a little problematic as placing the coral higher up the reef should provide sufficient light but perhaps too much seawater movement. When placed, watch the coral, does it expand properly and does the expanded coral look comfortable, that is not banging about in the current? It is easy to see when things are fine.

Having a pulse coral in the aquarium certainly adds to interest to state the least. If the pulsing action reduces or ceases, first be sure there isn’t excessive seawater movement. Then check for nitrate, if the level has increased reduce it by increasing the amount of routine seawater changes, at least temporarily. Investigate the reason for the nitrate increase and correct it. (The guideline for nitrate in a reef aquarium is 10ppm or less.) As a final check, all else having proved not to be the reason, check the seawater oxygen level, perhaps the seawater is carrying the maximum? Overall though, this coral should give little trouble.

The link below will give further information and photographs, just scroll down the page, lower down is a picture of a coral in action.

http://reefkeeping.com/issues/2004-02/ac/feature/index.php

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