It’s taken quite a while and there have been quite a lot of decisions to make. Before those decisions could be made research has been needed which probably meant the purchase of a good hobby book which in turn threw up a lot of questions. Thank goodness for the internet, a massive resource for information.

The decision on whether it will be a reef or fish only system has been made as well – of course it has, how else would the decisions on some of the equipment be made such as lights? So there the aquarium sits, full of seawater, all equipment running. The biological filter has been started and tests indicate all is ready. Seawater testing must continue through the stocking period and beyond of course. The new aquarist is nearly overcome by the desire to obtain livestock. Hold on a little longer though, the whole point of the system is to see healthy marine life so let’s not make a mistake with it.

Correct stocking means slow stocking with the correct species and this has to include consideration for further stocking later which means the first fish need to be compatible. There are fish available that are suitable for beginners and will not cause undue problems in the future. They are generally hardy and will forgive some novice errors which are often to do with seawater quality.

What if the system is to include a reef? The same thing applies: the corals need to be compatible and not a negative for the future and also be hardy (in marine terms). Though it is not absolutely necessary, it’s best to place corals in first and allow them to settle for a while so that they have the best quality seawater without the contaminating influence of fish. In addition corals usually arrive on a rock and this rock has to be fitted into the reef. This could raise the need to move or even remove rocks and new fish would be further stressed by this action. There are corals that are suitable for the beginner and could very well be enough for the future as they display beauty and interest together and individually. On the basis that corals are strictly best in first what is available?

The best corals to consider are those that are generally termed as ‘soft’. These corals come in various forms and there are many types. They provide a lovely reef scene and many sway in the seawater currents and make a lovely picture. The size of the aquarium needs to be considered to ensure individual coral types are suitable and also how many different types are required. Corals have a low impact on seawater quality, far less than fish, so that is one potential problem less. They should be firmly placed so they don’t fall later and have plenty of room for expansion. Corals should not be in direct line with a powerhead output. Some of the corals mentioned can be trimmed (‘fragged’) if they become too large, producing a new coral.

The first coral type is the finger coral (properly known as Sinularia sp and Lobophytum sp). As the name suggests they usually have a main stem attached to a rock with branches above which in turn carry smaller branches which hold the polyps. This is not always the case though, some are low level. One of these low level types is Sinularia dura which is possibly the hardiest of all but still lovely.

The toadstool corals (properly called Sarcophyton sp) have a thick stalk crowned by a flat head covered in extended polyps. They are quite unique in appearance and interesting to include.

Mushroom corals (properly known as Rhodactis sp and Discosoma sp) are a little similar to the toadstools but much lower. They are attached to rockwork by a short stalk and have a circular head. The head is usually of a rough appearance but not always. They usually form groups.

Button polyps (properly known as Zoanthus sp) are a grouping of polyps that appear similar to flowers in a vase. The heads are much smaller than the previous corals. They can spread and are usually constrained by the size of the rock(s) they can colonise. They are an excellent addition to a reef.

That’s a good start for corals so what about fish? They need to be compatible with corals and each other. Before a few fish species are considered let’s look at damsel fish. These are small, active, hardy and colourful. Some, even occasional dealers, still suggest them to ‘run in’ a new aquarium – this is wrong, maturation fluid should be used if required. Very important, damsel fish are generally territorial and aggressive. If they are placed in an aquarium first they will see the aquarium as their territory and could harass or attack later additions even those bigger than themselves. This could lead to the later fish being afraid to come for food resulting in poor health or death. So avoid damsel fish. If one must be had, introduce it to the aquarium last so that other fish are settled and ensure the other fish are sturdy and not easily picked on.

The first fish in this short starter list is the firefish (properly known as Nemateleotris sp). At first sight this fish species appears delicate but they are reasonably hardy and are best kept as a pair. They could grow to about 3”. Probably the best known firefish is Nemateleotris magnifica.

Another interestingly shaped and coloured fish is the bicolour blenny (properly called Ecsenius bicolor). This can also grow to about 3”. It moves from rock to rock and mainly stays in view, and could stop at a particular point for a while.

Now for the gorgeous royal gramma ( properly called Gramma loreto). This fish is a little larger and could grow to near 4”. It is beautifully coloured and a definite plus.

A fish that most would recognise is the so called common clown (properly called Amphiprion ocellaris). These could grow to about 3”. This clownfish bears the colours that signal ‘marine’, it is very attractive. Two could be kept. These fish are being widely commercially and home bred. It’s reported that the aquarium bred ones are more hardy than the reef caught ones, so it’s a very good idea to obtain the aquarium bred type. On the wild reefs clownfish live with anemones but this should not be attempted by the beginner. Keeping an anemone is not as easy as might be thought as experience is required. Common clownfish – particularly the aquarium bred ones – should be quite happy without an anemone.

If the aquarium is ready for stocking that is all is operational and the biological filtration is ready, the suggested corals and fish (or some of them depending on the size of the aquarium) should give a colourful and interesting foundation. They are reasonably hardy and are able – within reason! – to tolerate small errors beginners are likely to make. If the aquarium is big enough further fish and/or corals can eventually be added after research has confirmed that they are fully compatible with existing stock.

There’s something missing from this text – pictures. If the aquarist types the proper name into a search engine then a whole host of choices will appear, including pictures and care.

Of all the marine fishes that are available many are very beautiful, some are different and others are just individual. The longnose hawkfish is one of the latter and in addition it’s colourful. The proper name for the fish is Oxycirrhites typus.

The full length of the fish could be 5” ((13cm) though it is likely to be smaller in an aquarium. The system should be a reef as it is important that there are areas of rock and perhaps branching corals so that the hawkfish can ‘sit’. The aquarium does not need to be a large one – a three foot length is enough (though as with all fish the larger the better as it arguably becomes more ‘natural’). The fish is not a strong swimmer and tends to sit and watch for food before moving to a new position, so it follows that very strong seawater currents are not  liked. The only other demand the fish makes is good quality seawater which is the usual anyway.

Any fairly experienced aquarist looking round a marine shop on seeing this fish would feel cautious because of the long nose, in the same way as with say a copperband butterfly fish. However, unlike the potential for problems with feeding a copperband the hawkfish is not problematic. It will eat frozen fare such as chopped fish, mysis and brine shrimp and will also take suitable freeze dried offerings, plus flake food. The food the fish normally eats in the wild is very small crustaceans and even very small fish so this has to be born in mind to ensure  that an adequate diet is offered. Fortunately the diet generally ties in with many other fish type requirements. The fish is likely to eat any very small crustaceans it finds so a reef system could provide some. Larger invertebrates including corals are safe.

Another big plus for this fish in addition to it being peaceful is hardiness. The longnose hawkfish is hardy overall and with proper system maintenance should not be a cause for concern.

The longnose hawkfish is not always easily obtained and an aquarist who desires one could need to place a specific order with a dealer. Once the fish has settled into its new home it becomes a very interesting addition, the shape of the fish and the colouration being part of this. It’s very entertaining watching the fish perch on one of its resting points observing and hoping for food. Given time the fish will beg the aquarist for food, paddling to hold a position in the seawater – ‘come on then, I’m starving, get on with it, feed me!’

There are some spectacularly coloured marine fish and the mandarin fish must surely rank very highly among these. It’s a dragonet and the proper name is Synchiropus splendidus. There is another fish that competes for glory called the psychedelic fish properly called Synchiropus picturatus, the markings are generally circular. If I were to be the judge, the mandarin would take the crown.

The mandarin can grow to about 4 ins (10 cm) but is likely to achieve less in an aquarium. The environment needs to be of high quality as is always the case – for this fish it means high quality sea water in a reef system. The fish is not suitable for a fish only aquarium. There should be many rocks which afford many caves and crevices for the fish to hide in. The fish is not particularly secretive but needs suitable décor for security. Only one fish should be kept as two could cause trouble – two males are likely to fight. Advanced aquarists with a suitable large very mature reef system could cautiously try a male and female, the sexes are determined by the male having a first ray on the front dorsal fin twice as long as the female’s. The fish are reasonably tolerant of light from subdued to fairly bright.

It’s very sad that these fish are often bought by inexperienced aquarists and they are then for the most part doomed. Inexperienced aquarists should not obtain this fish and should resist the beauty of it. Even if the aquarist has a reef system that has been properly initially matured and other fish are healthy this still will not do. The problem is adequate feeding.

The mandarin fish spends most of the day moving about on the surfaces of rocks, algae and sand looking for food which consists of tiny organisms. Therefore the fish has a very small mouth. It could be, though it isn’t the norm, that the aquarist will find the fish will take some brine shrimp but in the longer term this will be inadequate. This is why the fish must be housed in a reef system so that it has the best chance of finding proper nourishment and the larger the reef system the better as the possibility of finding food increases.

So the guidelines are first and foremost do not buy a mandarin on impulse! Second, the aquarist should have some experience – it’s difficult to put a time period to this but say more than a year and seawater quality is continuously high. Third the fish must have a reef environment though this does not guarantee that there will be enough food whatever the reef size. Finally the aquarist must be willing to spend some more money to try to ensure the mandarin is properly fed.

Spending even more money to feed one fish? If a higher chance of success is required then yes. As already said even with a large and very mature reef system there isn’t a guarantee that the proper food will be available in sufficient amounts. A proper diet in sufficient amount is important to all life forms. So it will be necessary to spend some extra money at least at first and possibly continuously.

 Nowadays the marine hobby is very well supplied by the marine industry and this applies to food types. Available nowadays are ‘copepods’ which can be put into the reef system and on which the mandarin can feed. It’s necessary to monitor the amount required as far as possible (this is done with food for all fish anyway) and it could be that the amount added will diminish as time passes. Once the mandarin is in the aquarium and appears reasonably settled because it is looking for food, put in a batch of copepods. Observe for a week and then put in a second batch and again observe. The mandarin should be seen to eat as it ‘pecks’ at the rocks etc. If all seems well place more copepods in but this time after two weeks. If the mandarin appears to be finding food throughout this period leave another week (that is a period of three weeks) before considering a further introduction of copepods – and so on. Hopefully the introduction of food will be very much reduced as the aquarist finds an adequate introduction rate.

 The addition of copepods to the aquarium has the additional benefit that the tiny creatures generally are detrivores eating leftover food etc. When adding these to the reef system it’s a good idea to add a small portion to the sump if there is a deep sand bed.

 The mandarin fish (and the psychedelic fish) are wonderful additions to a mature reef system, but only if the aquarist is willing to give the fish the best chance of health. This of course applies to all aquarium life but particularly so to some specialist feeders. If the aquarist pays the price for success, the price being observation and expenditure on food as required, then the mandarin will remain in good health for a long time.  

Buying a new fish for the aquarium is without doubt exciting. We don’t keep aquariums just to look at a glass box! Even in a reef system fish make the scenery look more realistic and add movement. 

It’s assumed that all the correct actions have been completed before the moment of purchase. Above all else, the fish shouldn’t be an impulse buy, an act more likely to occur with less experienced aquarists. Obtaining a fish because it’s so pretty is wrong. The fish general type should be reasonably researched, that is it should be suited to the type of environment it is intended for (reef or fish only) and be compatible with the fish and corals, if any, already present or intended. The fish may look lovely but what is its final size? Does it have predatory tendencies? Particularly in a fish only system, but also for a reef the fish type’s character should be carefully judged as timid fish will not do so well among other bolder and more aggressive ones. Some research as above is important as once the local fish store is reached the fish on display, some very tempting because of their beauty, are likely to cause confusion. 

Fish for sale at a local fish store cannot be automatically accepted as being healthy. Some stores properly quarantine incoming fish and this has to be applauded. It’s necessary to ensure any quarantine has been properly done though – I learned of one store that did genuinely keep fish for two weeks before sale and then sold them. The problem was that the fish were not isolated for the two weeks in quarantine as new incoming fish were placed in the same tank. This exposed the existing fish to any incoming problem and each time a new fish went in the quarantine period should have been extended for a further two weeks (or more) but this didn’t happen. 

It’s important for the aquarist to question the health of any fish desired – spend time looking carefully at the fish for negative signs such as cloudy eyes, ragged fins, over fast respiration, hanging about listlessly in one area, spots and marks on the body etc. This is quite difficult for the inexperienced as for example fish have naturally differing rates of respiration. For example, a damsel has a faster gill beat than an angel. Also in a dealer’s tank the situation is far from perfect as the dealer needs to catch the fish on display quite quickly and a heavily decorated tank would seriously interfere with this. Nevertheless there are signs that can be spotted. If the store has a good reputation the assistant will be happy to explain anything. Once the aquarist is happy that all is well, ask to see the fish feed and again the assistant should be happy to oblige. If all is well ask the assistant what is usually fed – once home use this diet to start with so the fish recognizes the food if the species is known to be a bit finicky. The diet can be varied as time progresses. 

In the photo is a beautiful fish commonly called a copperband butterflyfish, the proper name is Chelmon rostratus. This is a reasonable example of what the less experienced aquarist should avoid. The fish though a ‘butterfly’ is generally suited to a reef aquarium but not a fish only system unless the fish are peaceful and even so food could be lost to other fish. A reef is best as the fish can pick at the rocks for food as it would in the wild, hence the long snout, though it’s unlikely the fish would find sufficient to eat. Even with a healthy fish the problem arises with standard feeding, with even experienced aquarists finding that they don’t feed. What is really frustrating is that sometimes they do feed without any problem – it seems to be a bit of a lottery. The one I owned lived in a reef system but I had to place food in a special rock with holes drilled in it so the fish could take it ‘naturally’. 

So the aquarist has picked the fish which is compatible and as far as can be ascertained healthy. It needs to be transported home and if not already quarantined put into a quarantine tank. Most aquarists don’t do this unfortunately. Then after a fortnight or more it should be properly introduced to the display aquarium, with dimmed light and time for the seawater condition between the quarantine tank or travel bag and the display aquarium to equalize. 

The first point when the fish is in the display aquarium is to watch for it to appear. Most fish tend to disappear into the rocks, or find a suitable place which offers some security. For all the fish knows there are predators about. Feeding the fish already present should continue as usual. The new fish will stay hidden for a while, the period very much dependant on the species and the company it has to keep. A healthy fish will re-appear and explore the aquarium. If the aquarist has provided sufficient hide-holes one of these will be adopted giving the fish more permanent security. Security is very important to the new fish as it has been stressed a great deal in the previous weeks with capture (unless tank-raised) and travel, so it needs time to calm down and resume its normal life patterns as far as possible. 

Once the fish has re-appeared a check needs to be made that it’s feeding. Some fish are bold feeders going for the food the instant it hits the seawater. Others are slower and some are timid, particularly if they are being harassed. The character of the fish should be taken into account to ensure it has enough food. Sometimes the fact that other fish are eating is sufficient for the new fish to join in. 

Whether the fish has been quarantined or not, once the fish is visible a watch should be kept for any changes in appearance or habits. If the way it swims changes, or breathing rates increase, or there are ragged fins it should be noted. If very small or tiny yellowish white to white spots are noticed on the fins or body then very close monitoring is needed. If the fish gives the opportunity have a look with a magnifying glass. Spots could be a sign of serious disease which if left alone could put other fish in danger. If such a sign appears don’t take immediate action but try to be sure that what is being medicated is actually there! Speedy action is necessary but there is time to consider. With some diseases it is easier to treat a fish only system than a reef. 

All aquarists keep a general eye on their fish to be sure they are healthy even if the fish have been resident for months or years.  After a time it becomes automatic at feeding and maintenance times. 

If the aquarist keeps high quality seawater and does the necessary ongoing maintenance plus feeds an adequate diet, with a little bit of luck the odds seem to be that the aquarium fish will settle and live a long healthy life. As experience grows the likelihood of being tempted to add ‘one more’ fish, possibly an inappropriate one, will diminish.

We moved address and I had to close my reef aquarium. It was a sad but necessary action. At the new address, once all the seemingly never ending jobs after a house move has occurred had been done, my thoughts turned to another reef aquarium. This one, the current one, is a little smaller because of space.

According to my notebook the aquarium was initially mature in October 2002 that is any unwanted ammonia/nitrite readings had gone. This was with an aquarium full of seawater and rocks, nothing else. I wanted a soft coral reef (as always) and a selection of corals went in. These were left to settle before any fish additions.

I always understock my aquariums and only considered three fish which needed to meet the criteria of being reasonably hardy and not over timid, also they would need to remain small. The selection was a Flame Angel (Centropyge loriculus), a Flashback as in the photo (Pseudochromis diadema), and a Fijian Blue Damsel (Chrysiptera tampou). Once the fish had been selected and given time to display any unwanted problems they went into their new home. This was in April 2003.

They were fine, no problems at all. They all fed really well and didn’t cause each other problems. After a while the Flame Angel became boss fish and the other two bickered with each other occasionally.

The whole reef continued in really good shape. The fish were in good health displaying excellent colour and no signs whatsoever of any problem. In time the Flashback became very rounded – he (she?) spent much time in amongst the rocks which I assumed was because tiny creatures were being caught and eaten. The Flame Angel did the same but to a lesser extent and the damsel mainly just cruised about in open water.

We all from time to time have some identifiable problem with an aquarium, in my case it has been with hardware – a powerhead became very noisy and had to be fixed, likewise with the protein skimmer motor. Not a big problem.

After three years, in March 2006 I noted that the Flashback had not appeared as usual when food was offered. The fish was often the first at the table even beating the damsel to the offering. Waiting and watching achieved nothing, the fish didn’t appear. I wasn’t particularly alarmed and the next day I expected the Flashback to appear as usual, particularly at feeding time, but the fish was nowhere to be seen. The fish, as were the other two, was in clearly good health. The only noticeable thing and different from the other two fish was the very rounded belly from the food available among the rocks.

Some fish have been known to jump though the Flashback is generally not one of these. However, as I run my reef with an open top I checked for the fish everywhere, on the floor all round the aquarium cabinet, everywhere that the fish could be on aquarium braces etc but found nothing. There is a weir for the seawater but nothing had gone over this, and it would be very difficult for anything to do so. I even checked on the top of the fluorescent tubes!

I continued to watch and hope for quite a few days but the fish didn’t appear. At this point I did ammonia and nitrite tests but these were normal at zero and remained so. There wasn’t any sign of a reef problem: all the corals were happy, extended and showing off their polyps.

So I wonder what happened. I have to admit that I haven’t any idea based on fact as there wasn’t any indication of anything amiss whatsoever, the fish was certainly in good health and mobile with no sign of age. It wasn’t a timid fish (they’re known to be the opposite generally). There’s certainly nothing in the aquarium that would predate on the fish. The only conclusion I can come to is that the fish paid the price for being greedy and getting well rounded, there certainly wasn’t any overfeeding by me but there’s quite a lot of live food in the rocks. Somehow, maybe, it got stuck in the rocks.

The Flame angel and the Fiji damsel continue in great health and colour having now spent eight years in the aquarium. I’ve not replaced the Flashback as the display is lovely as it is.

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.

The first time I was attracted to marine fish I was looking at damselfish, though I didn’t know it. The bright colours and full-of-life actions were a magnet to my eye. It was after that, and after speaking with the shop proprietor, research and consideration, that I moved into the marine aquarium world. It was a long time ago!

Damsels seem to be the ideal fish for the beginner and a good addition for those with experience, and they are. Generally they are one of the cheapest of marine fish, if not the cheapest. As with most things, however, there needs to be a pause for thought.

Most damsels are best known by their common names, for instance the Chrysiptera cyanea, better known as the blue damsel or blue devil. It’s always best to find out the Latin name of the species that is of interest as this should remove the problem of purchasing an incorrect type.

When the aquarist has seen the type of damsel(s) that are of interest, a check should be made to see if the colours that are so attractive will remain so. Some are very attractive when young but later will become dull, perhaps a grey or brown. One point that is of interest to a reef aquarist is that damsels are safe with corals and will eat only the very smallest invertebrates.

Generally hardy and easy to feed fish are good for beginners and damsels meet these criteria as they will tolerate less than good seawater conditions (not that they should have to) and will eat many foods including flake and frozen types (of a suitable size).

As they are hardy some shops advise that they can be used to initially mature, or cycle, a system. This is wrong and the fact they are hardy is not an excuse. No animal should knowingly be made to endure less than good conditions. Systems should be initially matured using easily available liquid products which are very easy to apply.

Once a system is initially matured damsels should not be the first fish that are introduced.  The guidelines indicate that fish should be introduced gradually so that  the bacterial system can mature to match the increasing load. This of course means that fish introduced first will be on their own for two or more weeks. This gives them time to settle and grow accustomed to their environment. If these first fish are damsels, it is possible or even probable that any fish introduced later will suffer. This is because damsels can be very territorial and aggresive. It is best to introduce other species first to give them time to settle and of course they will be part of the scenery when any damsels arrive. Generally speaking (there are always exceptions) the blue coloured types are more peaceable than the black/white and yellow ones. When young damsels could present no problem at all but may become more aggresive as they age.

It would seem then that damsels are not quite so good a choice. This isn’t so – they will tolerate variations in seawater conditions caused by inexperience such as overfeeding and other below standard husbandry, and are not finicky when food appears. All that is needed is for the aquarist to be aware of their potential character traits and act accordingly. Damsels make a lively and colourful addition to a display.

There are three types of marine aquarium and these are fish only, fish and corals (mixed reef) and corals only. If the aquarist has decided to keep corals only then there aren’t any questions to answer. The same obviously goes for a fish only system.

However, what if the aquarist goes for what is probably the most popular system, the mixed reef? What are the problems that could arise as far as the corals are concerned?

Generally speaking corals are more sensitive to poor seawater quality than fish meaning that the presence of fish is a negative from the start. Why should this be so?

Fish are generally the heaviest feeders in the aquarium and the larger the worse. Food and the end products of it cause seawater quality to deteriorate, for example the production of nitrate and the introduction of phosphate. The more fish the more pollutants. Poor seawater quality is combatted by routine seawater changes and good feeding discipline. Clearly, the aquarium should not be overstocked.

So all that needs to be done then is carry out routine seawater changes? The answer to this is yes of course, with a few more provisions. The guideline amount of seawater to be changed in the first months of the life of the system is 10% of the net gallonage (including any sump). The aquarist needs to carry out tests on a routine basis and keep a record of the results. There are several tests that are normally used for seawater testing, but the ones here are particularly nitrate and also phosphate. As already said nitrate is the end product of the decomposition of excess food and other organics and phosphate is mainly introduced with food.

Nitrate is a very useful indicator of seawater quality (but not the only one of course).Over a period of time the aquarist who has kept a note of test results should see a trend which will indicate the deterioration rate of the seawater (sometimes nitrate doesn’t appear or disappears after initial maturation). This trend will indicate to the aquarist the need or not to increase the amount of seawater routinely changed. If the nitrate continues to increase check the dry salt mix though nowadays this should not be the problem. It is also worth checking for nitrate content in the water being used to make the salt mix. 

If excessive phosphate is detected then again the dry salt should be checked though as said is not likely to be a problem. A check of the water used for the mix should be made. Phosphate is more likely to appear in a system containing fish.

So an aquarist with a corals only system is likely to find, all things being equal, that a seawater change of 10% is adequate. If there isn’t any indication of nitrate then it is worthwhile continuing with a 10% seawater change as this ‘freshens’ the seawater and adds some trace elements that are lost because of protein skimming as an example. Experienced aquarists could decide to reduce the seawater change amount a little, but routine seawater changes should not be abandoned. Of course, dependant on the type of corals kept other supplementation such as calcium could be needed.

There are few aquarists who are satisfied with just corals. For a start, the scene seems to appear more natural with fish present. However, once fish are present then seawater deterioration increases. How should the aquarist proceed?

In an ideal world the corals should be introduced first, permitting them to settle and also permitting the aquarist to be happy with the reef  layout. This procedure is not essential but is a good practice. After a few months when the corals are clearly healthy and settled the question of fish can be considered.

In a fish only system the stocking can be to the limit of the net gallonage (excluding any sump). This is not so in a mixed reef system. To assist with the maintenance of high quality seawater the stocking levels are restricted.

Again there is a ‘best practice’. There isn’t a requirement to have lots of fish as there already is a lovely and developing coral scene. Also the fish need to be fully compatible with the corals, it wouldn’t be pleasing if coral was a tasty lunch. They should not be too large, permitting them to move among the corals easily, small fish are usually the best and there are some really beautiful ones. The aquarist should add  two small fish first (hopefully after they have been quarantined). Once a minimum period of a month has passed all should be well with the fish settled into their new home. The aquarist should consider if his/her creation is sufficient, that is, is there a need for more fish? It could be that there isn’t. If there is, then add two more fish and again leave a month and re-consider. To repeat, there isn’t any need to have lots of fish. The movement of a few fish complement the already lovely reef scene. Under no circumstances should the maximum stocking guidelines be exceeded – and remember that fish grow. The stocking guideline for a mixed reef is a maximum 1″ (circa 2.5cm), excluding the tail, to 6 gallons of seawater, excluding the seawater in the sump. 

Using the above stocking method the aquarist is protecting the all important seawater quality by reducing the pollutants that are introduced into it. This in turn should reduce the size of the required routine seawater changes provided the fish numbers have been minimized. The result should be a mixed reef to be proud of.

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)

Most marine aquarists are only too happy to have something different in their aquariums, as long as that something fits in with the current population.

The apple being talked of here is the Sea Apple which is definitely different! As can be seen it’s colourful too. An aquarist who has one will usually be fascinated by ‘the thing in the corner’. The Sea Apple has been available to aquarists for many years. I feel that the beginner aquarist should let experience build before keeping one, as a pure guess say about a year, or at least until the common general husbandry mistakes are no longer made and seawater quality is consistently high. This is important as will be seen.

‘Sea Apple’ is the common name; the proper one is Pseudocolochirus axiologus. They need the usual correct introduction to the aquarium, that is, acclimatization, and should not be exposed to air. They need to be handled gently but this of course is the same for all livestock.

The Sea Apple does not require reef lighting as it is not a coral but a species of sea cucumber. This can of course be confusing, the common name talks of ‘apple’ yet the species is ‘cucumber’. (This seems to happen from time to time, such as the Foxface fish (Lo vulpinus) that belongs to the rabbitfish family.) The Sea Apple is usually able to grow to about 4″ (circa 10cm) though there are larger species that grow to about 6″ (circa 15.25cm) or more though these are not so readily available and are more expensive.

The Sea Apple is able to move slowly around the aquarium and will do so until it is happy with its position, and this depends a lot on seawater flow. The flow doesn’t need to be very strong but moderate to brisk. This is because from the top centre a crown of feathery tentacles will appear and too strong a flow could cause problems. As said, the Sea Apple will make its choice and the final place could be a viewing glass, a corner, a rock or even the tube from a tubeworm. The aquarist has his or her preference for position, so keep those fingers crossed. The final position is likely to be between half way and the top of the aquarium. Once the Sea Apple has come to rest it should be left in peace unless the position is causing trouble to other livestock or presents a danger to the Sea Apple itself. It should not be irritated by the aquarist; this could be a real problem as will be seen.

The tentacles are used for feeding and are extended into the seawater column for this purpose. Fine particulate matter is captured and, one by one, the tentacles are passed into the mouth for removal of any food and then withdrawn, it’s a bit like a human sucking food off the fingers. This is a fairly slow process and is fascinating to observe.

The Sea Apple is quite hardy in a high quality environment and can live a long time. Many do fail though and this is to do with feeding, or rather the lack of it. In most aquariums there is insufficient suitable fine particulate matter in the seawater and therefore the Sea Apple doesn’t get enough to eat. This causes it to slowly shrink until it dies. Target feeding is needed, the frequency of which is best twice a day or more if the need is observed. There are plenty of commercial fine foods available that are suitable. All that is needed is for this food to be squirted into the seawater with a suitable instrument a little upstream from the Sea Apple when it has the tentacles extended, the food will then drift over them. If the seawater current is too high causing the food to pass too quickly, turning off the pumps for a short period will not do any harm. Any of the fine food that is not taken will drift off and could well be captured by corals.

Overall I would suggest that a reef system is the best aquarium for the Sea Apple to be introduced into. The reason is that there is a greater likelihood that there will not be any fish present that could nip at the tentacles, though this is not always the case. If the Sea Apple is excessively harassed then serious trouble could occur.

The problem that a Sea Apple could cause is very serious. If it is excessively harassed and stressed a toxin could be released that could, and likely will, kill the other livestock. Not a pleasant thought. That is why the Sea Apple should not be harassed excessively by the aquarist and its tank mates should be suitable. In addition it would be a good cautionary measure to protect the intakes of circulation pumps etc so that the Sea Apple cannot be accidentally damaged, this should be done before introduction.

Having said that, the Sea Apple should be a good introduction to a suitable high quality environment provided the aquarist has reasonable experience and feeding is given suitable attention.