Caring and Propagating Acropora

Introduction

I would like to say that all of what I have written below is just my way of doing things and some are ways I have been told how to do things that I have put into practice and works for me. My reef aquarium is very likely different to yours so some of my methods may not work for you, but some methods should be able to work for you too. I am sure there are many different ways of doing things this is what works for me.

Caring for Acropora

To keep and care correctly for Wild Acropora's and some SPS corals extra equipment and types of equipment can be more expensive than equipment when keeping many types of soft corals. You may need equipment and extras that you do not need with many types of soft corals and some LPS corals. If you are on a budget then I would suggest you stay with hardier and easy to care for corals. The problem is that many people can keep certain types of soft corals successfully in all sizes of tanks with out using very much equipment and a small amount of water turbulence and lighting. From this success you then wish to try the many types of LPS corals available and mix them in with your soft corals.
Again this can becomes successful and some of these LPS corals expand very large. (Could be they are spread so large because they are not supplied enough lighting meaning they may expand larger to receive maximum light available just a theory not proven?) You can end up having to keep rearranging your Soft corals and LPS corals to keep them from touching. Some soft corals can harm other soft coral and more often LPS corals will harm soft corals if touching. And because of this success you then feel you can try SPS corals some of the hardier SPS corals may grow. But may grow slowly depending on type and may lose colour pigments maybe due to an increase in density of the brown Zooxanthellae that may hide the colour pigments. But then a lot of the clear shallow water species do not receive sufficient light in our aquariums and they may bleach fast or slowly and maybe through stress on top of every thing else will not adapt and never recover. The conclusion is made that they are too hard to keep and many people do not realise that it is down to water movement and lighting and water parameters I hope to explain later in this article.
I have been there and could not get help and advice and I am still learning and researching and still making some mistakes and do not know how to sort out what parameters are wrong. But now I understand a lot more of how to care and raise these SPS corals but sadly through great costs in mortality and money. There seems to be a lack of knowledge in our hobby here in the UK on the subject of care and advice for SPS corals. I do not know it all and still lose the occasional colony and cuttings sadly.
But the upgrading of certain equipment and husbandry and methods is helping to keep them alive and healthy and sometimes colourful and propagate them but do have some failures and setbacks. I feel I should pass on the knowledge I have gained so that others can have some understanding of what is involved and needed before they attempt to keep these corals. Or if they are keeping sick SPS coral this article maybe will help to give some understanding of why they are having difficulties and how and what is needed to correct it. And hopefully less of these types of sps corals will die through lack of understanding and advice and equipment. And with any luck more people will know what is involved in keeping them and costs involved and may be able to propagate these types of coral increasing the survival rate of them in this country.

Buying Acropora

Many wild Acroporas from shops are described as Acropora Spp and unfortunately are not kept in correct conditions and there is not any knowledge of the care and equipment needed to keep them successfully in this country. Most seem to come from one source T.M.C. and no advice is past on with these coral by them. I am sad to say that the trade that supplies these types of corals and certain other type of corals do not have knowledge of these corals or conditions needed etc and these corals seem to be doomed. The type I have mainly seen so far from these sources are the type that spread out ward over the rock they are attached too with lots of finger type branches from one to three inch high. The base may have a spread extending slightly beyond the main group of branches with many polyps this part is sometimes the main growth area they can grow new branches from here and the base may spread over the rock in this type of Acropora.
The branches do have growing tips and are colourful under correct conditions but these tips do grow very slowly compared to the large branching types that grow new branches from their branches and upwards with very little spread at the base. It would be far better in my opinion (IMO) to purchase the branching type as they do not seem to need as much water movement or as much lighting which may make it easier and cheaper to provide the environment needed to care for them. Before you go to buy your Acropora and other SPS corals there are a few things to understand first before you decide to purchase these types of corals.

Water Parameters

Water Temperature and S/G could be better if it is closer to that of the area that these Acroporas and other SPS corals come from. Their seems to be a view that s/g should be kept lower than natural levels why. It could be that when keeping fish only systems it seemed to help but IMO to continue to keep s/g levels lower than natural s/g levels in a reef aquarium is incorrect. There is a major debate over Temperatures and the S/G that the hobbyist should keep his reef aquarium at it can very between Temps of (24c) 75f to (30c) 86f and S/G 1.020 to 1.027. IMO I feel we should keep the S/G in the range of natural seawater from where the corals are collected from this seems to be around 1.025 to 1.026 I feel this would be a better level to keep our reef aquariums at. For temperatures it is more complicated I feel it would be better to keep the Temperatures some where between (27c) 80.6f to (29c) 84.2f. Good water turbulence through out the tank and at the surface and some protein skimming may help to keep the oxygen levels high I will go into this at some other time. I find a temperature of 26c to 27c at present ok but I will be creating more turbulence and surface skimming and will increase Temps to (28c) 82.4f to (29c) 84.2f I will report back on this some other time. I use a cooler because the metal halides designed at present supplied to this country are not designed to incorporate two fans in the unit. One to blow air in and directly over and around the bulbs and the second to extract hot air out of the unit should give good air extraction in and out and through the unit. Lighting will be explained later and this will explain why the cooler is needed for some other reasons as well as above. My nitrates are stable at 0.2 but some times get to 0.5 best test kit to use is the seachem for these readings (of course ammonia 0 and nitrites 0). Phosphates again are stable at 0.03 but some times get to 0.1 but never higher Salifert kit. My PH is a tad on the low side at 7.9 first thing in the morning to 8.0 just before the halide lights go out. I think this could be causing some problem but I am not sure and I am finding out the best and safest way to correct this, I will add it to this article how I did this in later notes.
I use a seachem test kit at present but will upgrade to a good quality hydrometer very soon. Iodine I keep at around 0.05 it takes some time to get the water levels to this level I use a dosing pump but a drip feeder will do so long as it feeds in slowly over a week period at a time. I find the salifert test kit the best to use. Once a level of around 0.05 to 0.06 has been achieved I tend to stop dosing but test every two weeks or so (I use seachem reef iodine liquid) when the colour pink of the test kit fades to 0.03 this can take several weeks or more. Then add a weekly dose over a few weeks until you are back to 0.05 to 0.06 again then stop using again. I need more info and research on this. I use a Knops calcium reactor to keep a stable KH calcium strontium levels. KH is kept between 12 to 14 (seachem test kit) Calcium is kept to around 450 (seachem test kit) strontium is around 10 (seachem and salifert test kits are used). I am not sure of these levels yet but will be doing research in this area. I feel the longer you keep you reef aquarium you get into a routine and feel for the system you keep and find you do less tests unless you find something amiss in you aquarium if this is just experience or over confidence. I feel that when we keep a coral or corals and if they are known to be tricky to keep we should go back to the details of full testing and recording etc. Until we learn how this coral behaves what likes what it does not like And once we have a feel for it then you can lapse back into less testing etc. UV units could cause a major decrease in beneficial organisms that are beneficial to every thing in your Reef Aquarium. It would be better to use a UV unit in a fish only system or the local Marine shop or a marine mail order company. If you are going to add fish to a reef tank you should do as much research into the compatibility of the fish and to the corals you keep. It would be better IMO if you quarantined the fish your self before introduction into your reef again it is important how this is done.

Water Movement and Water Turbulence

This is very important and needs to be correctly done. There are many ways to use and apply water movement to corals this is just one method I use with good most of the time but their can always be one tricky coral that seems to defy what type of movement or method you try and supply. You should not direct a water outlet or power head outlet directly at an Acropora Or any type of SPS coral this can just strip the tissue off these corals. The methods I use as I have lots of SPS corals in my show tank is to use a mix of 10 pumps and outlets of different water flows and add more as you propagate and add new species. It better to add them at different levels in the tank and angles etc and aim some flows to meet each other which gives flows in all directions mainly downwards and a few of them on wave modules or plug in timers IMO. Also it may be helpful to place small rocks in direct flows between corals and pump outlet to break the flow up a bit on some of the stronger flows that are direct at the coral. So long as the direct flow from these outlets are strong flows directed above or below or to the side or broken up these coral can thrive. A method to test that you have a good movement of water through the branches of these corals is use turkey baster filled with bits of different sizes of food and detritus etc. And gently deposit this into the branches of these corals. Then observe if the food over a minute or so is blown one way or another from out of the branches and the bases where the branches grow from then if all is removed then the water flow through the coral is good. (when checking this out you must realise that if the Acroporas have good polyp expansion then the polyps may trap some of the food and detritus particles allow for this when evaluating the water flow through the branches).
Of course if this stuff added to them settles and stays in the branches and base then you need to adjust the water flow (but not directly at the coral) until the flow keeps these corals clean of any build up of detritus or food etc. The method above does not always work to how much movement is needed. The more water turbulence through out the tank the better.

Lighting

The first problem with this type of Acropora is getting enough light through the branches to the base. The type of lighting you use has to be Metal Halide as VHO tubes will do but are very hard to get hold of. It is thought that metal halide is best to use for intense light loving corals. The type of VHO or Metal Halides has been in a major debate over in the US I will try and explain a little about Acropora and lighting. Wild imported colonies of acropora are often from just below a very clear water surface and at very low tide they can be completely out of the water for a few hours. They receive very high light output and turbulent water movement. So You really need to try and get as close as you can to the sunlight produced in this area. 150w and 250w Metal halide bulbs do not approximate natural sunlight in shallow clear waters.
400w Metal halide bulbs provide a better approximation of the light some wild colonies come from. Fragments almost always photo adapt easier to lower wattage halide bulbs but not always. Distance of bulb from water surface can be of much benefit to these light loving corals. The 12" that is suggested by manufactures and hobbyist is a convenience to the hobbyist not to the intense light loving corals. Lowering the units will increase heat of the water and can restrict access into the tank ok but there are many ways around this. I am keeping all my Metal Halide unit bulbs at min of 5" from the water surface but can be raised and moved for access and acclimation etc. The type of Acropora described above will need to be placed so the tips are two to four inches below the water surface especially under bulbs less than 400w.
It would maybe better to start them lower down and bring them up to this position over a few days to allow for adaptation from holding tanks and shipping and shop lights etc. A range of fluorescent tubes on timers may be beneficial to be use for sunrise and sunset. If you do not get enough correct type of light to the base then the base may fade and over time and can bleach and then RTN can take hold and Slough off the tissue very fast. And once the base has bleached which is the main growth area for this type of Acropora the branches may slowly die. The coloured tips may fade to the colour of the lower part of the branches. I have described some types of bleaching in an addition.
If you can afford it 400w Metal halides may decrease problems and may help with keeping colour pigments and improve the growth rate. If you have 250w or 150w placing the Acropora directly below the bulb is maybe best. But if you have more than one of this type of Acropora and one bulb then place the other Acroporas as close as you can but do not let them touch or shade each other's bases this will create problems as the corals grow and spread. If you wish to have an aquarium devoted to intense light loving SPS corals It may be better to have 400w Metal halides. (You will notice that when handling these Acroporas they give your finger tips a funny tingling sensation) You will find that maybe the area that is shaded the most may bleach. But the areas with the most light will darken and start to colour and make up for the area that is bleached so long as most of the base receives good light and is darkening up and colouring up. Position of bulbs in relation to water surface seems to be between 7" to 3".

Aquarium

A useful dimension IMO is the back to front measurement a minimum of 24" as the top will need to take all your wild imported light loving acroporas even more so if you are using less than 400w bulbs. And if you are keeping the bulbs high above the water surface you may not be able to supply enough light. Lower down will be needed for all the cuttings and less light requiring SPS corals and if you have the space LPS corals. Depth of the tank over 12" you are best getting 250w 400w Metal Halides and also the deeper you go increase the wattage. Even 12" high tanks may benefit from 400w lighting. As the back to front dimensions are increased beyond 24"then extra lighting is needed.
Length next again the longer you go the more metal halides are needed and how many SPS coral you will keep And if You have the space LPS Corals as soft corals mixed in you will may have constant warfare may cause problems. If you want soft corals be careful what you choose and limit the amount and keep an eye out for any problems. Mixing stony and soft coral may cause problems. Fish keep limited and smallish and compatible and useful.

Rock Work

It is better to really use good quality live correctly cured rock. Dead unlived rock can be used behind the live rock. The more live rock you can afford will help to give you the water parameters needed earlier. You can build the rockwork on top of egg crate that is 1" off the bottom of the tank and leaves about 7" at the front for 1"to 2" depth of aragamax aragonite sand (very fine). And then lean the rockwork on the sand and edge of the egg crate leaving six inches for the front sand bed. And build your rock up from there. A pump connected to pipe work running under the egg crate at the back with holes spaced evenly along it and facing forward and slightly down to the bare base under the egg crate this will keep the base of the tank under the rock work clean. The pump will need good pre-filtering to stop a build up of muck blocking up the holes. Make sure you have the height and depth (back to front) at the top to get the correct placement and area to take the mother colony's of Acropora and pocillopora the other type of SPS corals may be able to go lower if you use lower wattage lighting. Allow for adjusting this rockwork to achieve this and make sure you have enough live rock to get the height. There are so many ways rock work can be built up in the tank I can not say what is the best way to do it only the method I use.

Protein Skimmer

I use a counter current skimmer and a air pump I don't know which type of skimmer removes the most amount of beneficial microbes but I hope sometime to work it out. But all protein skimmers will remove beneficial bacteria's and trace elements and microbes etc out of the water. So you may need to feed even more food the more the skimmer becomes efficient and maintenance becomes even greater and you then have to start dosing extra element etc. I am designing additions to my tank so I may be able to do without a skimmer but I do not know weather this would be beneficial until I try. Will keep updates of the info I find on the use of protein skimmers.

Pre-filters

Pre-filters were an important method in the methods that I was keeping SPS coral I once thought. These were large and built into weirs at the two rear corners of the tank with bottom and top inlets. Extra external pumps and some very small internal pumps are added for extra water movement. When feeding dead and frozen types of food this seemed a good method of keeping down dead waste. (I have to say that this method of pre-filters is being changed.)

New Changes

I am in the process of making changes to my system I will explain the change I am making. First I have patches of turf algae in places in the main tank this does not spread out of hand and I feel is beneficial also a lot of bubble form on these turf algae patched and are their all the time of the lighting period.
I will be adding a refugium in the room above water will be pumped up to it and water will siphon gravity feed back down to the main tank below. I intend to light the refugium when the lights are off on the main tank. And the lights off in the refugium when the main tank lights are on. A 3" live aragamax sand bed some live rock and algae's and critters to inhabit the refugium. Once the refugium has matured for a couple of weeks and then I will remove completely the pre-filters and spiral filters in the main tank. But will first remove one pre-filter and spiral filter first and wait a weeks and then remove the second pre-filter and spiral filter. And hopefully this will create a flow of natural plankton between the refugium and the main tank gravity feed so as not to harm the plankton through pumps. And a better circulation of plankton and phytoplankton's etc in the main tank but some of these will be killed by the pumps but a continuous new supply should counter act this. And the refugium hopefully to increase the o2 in the main tank when it is not lit. I intend to produce more of my own live foods to increase the plankton and phytoplankton in the main tank and try to cut out as much as I can of the feeding of dead and frozen food. I will increase the temperature when the refugium has matured a bit and the pre-filters and spiral filters have been removed to 82f to 84f. This of course will change some of the maintenance routine. When feeding dead foods and cleaning rock work down pre filters will be inserted for a couple of hours and then removed.

Maintenance and Feeding

I give a regular small two-part weekly water change of between two gallons to three gallons maximum twice a week. (My tank holds 120 gallons and I change between two to three gallons total split into two changes over a week). Use RO-water and before you add the salt use could use a RO-adjuster first then mix up salt to a lower salinity to allow for evaporation you should test your salinity every day and adjust the water with your two part weekly change. If you only change you water once every two to four week there could be a lowering of trace element. Topping up with just RO-water is ok but that and longer gaps between water changes you may have too regularly add extra trace element. If pre -filters are used then it would be best to not leave them longer than 3 days. Also 10% and 25% water maybe harmful to some types corals and so are monthly 25% etc the smaller changes and more often you change the water the better IMO.
Feeding your corals and Acroporas is important. The views that corals do not need to be fed because the Zooxanthellae will provide all the coral needs is not proven. (If you have the time and patience and finances a refugium would benefit and growing your own nano and phytoplankton and rotifers and hatching brine shrimp larva and growing them on is maybe better. But flake and dead and frozen foods are OK but more maintenance is needed and the use of a pre-filters may help). Corals come from nutrient poor water true but there is heavy Plankton levels Phytoplankton Nanoplankton etc that raise in the water after sunset that all these corals may feed on. Too not feed your coral to keep your nutrient levels down may not benefit your corals. It may benefit to feed at lest twice during the day and twice after the all the lights have been out for few hours. Good maintenance when feeding dead foods is what is needed good pre-filters may help if used for an hour or two when doing this and then remove always leave all the pumps on when feeding so that with good turbulence the dead food stays in suspension for at lest several minutes so that the pre filters remove a good percentage.
A cleaning crew of coral friendly shrimps, hermit crabs, brittle stars, a tang etc helps to stop detritus build up. As these creature stir up the rockwork and sand at the bottom of the tank so that it gets caught up in the turbulence and helps to stop a build up in one place. Blowing down of rock work once a week may be an idea and to insert pre-filters for a couple of hours to remove excess detritus build up and then remove them. Stir up the surface of the rockwork with a turkey baster and a brush and maybe even a small power head this keeps the build up of detritus and things that build up suspended in the turbulence. And the pre-filters should remove a good percentage of this muck then when the water is clear again change the pre-filters. Don't forget the bottom section of the tank should have good water turbulence too.
I think that the corals you care for should be given the chance to live for the rest of your life time if you can not give them the care they need don't keep them. There are many other things that can be done but I will write about those in a different article and adjust this one if changes take place. At the end of the day the temporary use of pre-filters and blowing down rock work and sand bed and algae's etc and when feeding dead foods is just a different method of temporary vacuuming out detritus in the Aquarium.

Extras

The lazier you get the more problems you could get. Acclimatizing newly purchased SPS corals into your tank has been added to my additions.

Propagating

The lazier you get the more problems you could get. Acclimatizing newly purchased SPS corals into your tank has been added to my additions.

• 1 pair of pliers type wire cutters
• A tube of thick super glue gel
• 2 Tupperware containers or plastic containers
• 2 towels one dry one tank water wet (When ready)
• Half a gallon of tank water (when Ready)
• Kitchen paper towels
• 1 toothbrush
• And a steady gentle finger grasp

Arrange the equipment and stuff above on a work surface with plenty of room for every thing. Remove your half a gallon of water from the tank into a 10-litre bucket and wet one of the towels. Fold the wet towel to about a 12" square area on the work surface and lay out your pieces of 3" plus diameter live rock onto it. Scrub the area where you will attach the cuttings with the toothbrush rinse with tank water and then dry the area with the paper towel. Fill a couple of tubs with tank water. Then take out the Corpora from the tank and place it in the one of the tubs. Take the Corpora in one hand by the base rock it is attached too try not to touch the coral and the wire cutters in the other hand. Choose three branches to cut the size of the cuttings should be no larger than half an inch in length and check there is no tiny crabs in the way as you do not want to harm them. (the reason behind my view of no larger than half an inch in length is the closer you cut to the active growing tips the more active the cutting will be the further away you cut from the growing tip the less active it is but this does depend on the type and growth of the SPS coral etc). Then hold the Acropora nearly upside down over the plastic container containing tank water only and cut the branch off the branch will fall into the water and settle on the bottom with out harming it repeat until you have three branches cut. Return the mother colony to the container you took it from and then take the container to the tank.
Take the Acropora out of the container and position back from were taken as close to how it was as you can tank. Repeat this process with any other Acroporas you may have or wish to propagate. Now with the mother colonies positioned back in the tank you can now start with the cuttings in the tub. Lay out a section of kitchen paper towel pick up one of the cuttings out of the tub do not squeeze the cutting as the tiny cups that protrude were the polyps come out from are fragile and damage very easily. Lay the cutting on the paper towel and with another paper towel dab the base very gently where the cut is to dry it. Then take the tube of super glue gel open it and check it squeezes out. Then pick up the cutting very gently with one hand being careful not to transfer any glue onto the side and tip. And with the other hand take the tube of glue and dab a very small amount to the cut base so that a very thin layer of glue seals the cut part. Then still holding the cutting squeeze an amount onto the piece of rock you have prepared and are going to attach the cutting too. The amount of glue you use on this piece of rock to hold the cutting in place is difficult to judge when first doing it as to little glue and the cutting may get detached by grazing turbo snail or hermit crabs. It is also important that the area of the rock you will attach the cutting to has been cleaned and dried well plus the base of the cutting is also dry. I suggest that you give a dollop that has a larger radius than the diameter of the cutting and at lest a couple of mm depth. Then gently with very little pressure insert the cutting into the glue making sure that there are no gaps and the edges are embedded prop the cutting upright until it stands up on its own about 5 to 10 seconds.
Then place the rock with the cutting attached to it gently into a plastic container filled with tank water so that it will cover were the cutting is attached to the rock and the glue is fully submerged. After about one minute or so the cutting will be solidly attached to the rock then take it to the show tank and you can place it in the tank and it does not need to be so high in the tank as the wild mother colony's. (I have only the occasional cutting that gets dislodged by turbo snails or hermits using this method and fewer detachments the more cuttings I make). By only using super glue gel the cuttings do grow over the glue very quickly and then take a little longer to spread onto the surrounding rock. (The next batch of this type of cutting I do I will give a two inch diameter thin coat spread of super glue gel to the rock surface before I attach the cutting and see if this speeds up the growth spread of the cutting).
Wash your hands and dry them so as not to get glue onto the cuttings above the break and repeat the above process until all the cuttings are in the tank. Then you can sort out the flows and good lighting for the cuttings to how I explained earlier in this article. I have some new methods for taking cuttings from sps coral I will put in additions. Also I have been given several methods of propagating branching LPS corals I will report on this later of how this has gone for me.

Additional Notes - Buying, Lighting and Bleaching

Placing the tips of Acropora directly under Metal halides 2" to 4" below the water surface when first acquiring a wild imported Acropora can distress the Acropora and cause it to bleach as in tissue dying, recover, change or stay as it is.
There are a few things to consider before placing an Acropora 2" to 4" from the surface under Metal Halide lighting.
When purchasing Acropora spreading base types (A. humillis, A. gemmifera, A. monticlulosa A. tenuis, A. cerealis, A. nasuta, A. valida, A. secale, A. divaricata, A. cytherea, etc) Take your time checking the base has the same even colour as the branches below the tips and that the polyps are extended at lest a little.
Check what type of lighting is used over the Acropora in the shop tank. (You may have more powerful or less powerful lighting than the shop).
Check position the coral has been placed in the shop tank (distance of Acropora from water surface, distance of bulb from water surface, direct or indirect, water outlet position, water movement through the Acropora) (And is the Acropora shaded by a glass support or glass covers etc as this will lower the correct light levels). The Acropora could be in incorrect water and lighting conditions in the shop tank or maybe in the correct position and parameters.
Try and get the shopkeeper to give some information on water parameters of the tank type and wattage of lighting pump sizes and scientific names and species if he knows area of collection in the wild and how long has he had it and any history. Take written notes of all above.
If the Acropora is going to be placed in a tank with less or the same lighting that the shop provided place it high up and view it for 24 hours. Over this time study the new coral you may notice something that you missed in the shop.
Does the base have a faded look is there any bleaching on the base edge or center if it does then keep it high in the tank. If the base is the same as the branches etc then place a bit lower in the tank but check the base area at least twice a day every day for any signs of the base fading or whitening. (it can look fine for a month or more and then the base can fade etc) If it does then move it closer to the bulb in stages.
You may notice that the base when viewing at the shop is faded but looks healthy and good polyp extension and buy it anyway place this type high in the tank straight away after cuttings.
If your lighting is more powerful than the shops then place lower in the tank and over time even if it stays healthy move it higher to the bulb in stages.
Constant observation and quickly acted on corrections is what is needed.

Types of Bleaching I Have Experienced

Tissue has stripped from the Acropora killing it.
(Common when first started keeping). Very slowly dying tissue from the edge of the base up leaving behind a bleached white area and within a few days brown diatoms take over this white area. (polyps stop coming out totally on the whole colony). Then some time later a type of green algae starts to take over from the diatom areas. This can all happen on one Acropora over months until the coral has completely bleached and died. (No sign of tissue hanging off blowing off coming off the coral viewable). (Under a stereo microscope the area that is bleached and the area with intact tissue is now swarming with and being eaten by microscopic flat worm type things? I think these are opportunist and invade at a later stage of the bleaching process and are not the cause of the reason why it was bleaching in the first place).
(Common when first started keeping). Acroporas can to start with over weeks bleach like described above and then over night fully bleach with visual signs of the tissue blowing off (under a 1600x oil immersion compound microscope there seems to be a larger amount of bacteria than when viewing a normal colony I don't know what I am looking for or how to stain slides yet etc but I am getting books on this and hope to learn).
(Rare first loss this way recently only one Acropora very thick branched brown spreading type). Tissue swells up around the branches looks faded and on close inspection you can see the tissue pulsating swaying like an open brain coral when inflated. When extra current is applied the tissue just blows off the branches leaving behind white dead bleached branches This type of bleaching I think could be down to too little water movement around the very thick 1"+ branches.
(Rare occurred only once). The whole Acropora fades a tad and polyps stop coming out over time then over night its completely bleaches white with very little tissue remains left.
Small rock with cutting attached been dislodged left upside down getting no light for 48 hours and plus when repositioned with good lighting has partially bleached and will completely die and be covered in diatoms. (My carelessness and have lost cuttings by placing to deep in the tank).
Looks like Bleaching White But Not Losing Tissue or Dying
(Rare has been happening for 4 wks now and still occurring). One of my Acropora started out medium brown and light brown base and lower part of the branches over two months ago. Over five weeks or so this coral fade completely to just a tinge of brown and then faded to white Thinking it would die I waited for the brown diatoms to invade and three weeks later still no diatoms. When viewed from the front glass and all the lighting is on this coral looks white and no polyps are out. When the lights are off and viewed from above the colour is pink but still no polyp extension, and viewed from the front with a torch a tinge of brown to the under sides of the branches and patches at the base and the top parts that receive maximum light are a pink tinge. I will have to wait and see how this one turns out.

By Martyn Hulyer