The Feather Duster Worm

Reef aquariums could be home to many life forms. One of these is the obvious, fish, in many aquariums these are small and inoffensive, and in bigger systems larger varieties could find a place. The major consideration with fish is that they are reef friendly.

Quite apart from fish there are many varieties of life. As the systems in this case are reefs the next is corals, both hard and soft. The corals are really what make the display a reef, the rocks may be ‘live’ and there may be fish flitting about, but it is the corals that make the picture.

Seen less are sponges as these are considered difficult by many aquarists and therefore they are not always attempted. It is reported that many sponges are not as difficult to keep as imagined, but their demise is often because of poor collection when damage is caused or when the sponge is allowed to come into contact with air. Algae can be another sponge enemy.

A spectacular life form that could be kept in a reef aquarium is a worm. Not just a worm though, this one is a real show off. The worm lives in a tube and is considered very attractive because of the head of feathery tentacles that appear. They are expanded into the seawater in order to trap food. The expanded tentacles do look similar to the old fashioned dust mop or feather duster that tackled cobwebs etc in days of old.

The worm is understandably commonly called the feather duster worm, or sometimes the peacock worm. The proper name for arguably the best is Sabellastarte magnifica. Feather dusters are common in warm seas and are usually easily obtained from local fish shops.

The tube extends from the rubble or rocks but all of it is not usually in sight. The tube could be up to 6 inches in length and the extended tentacle crown could be between 2 and 3 inches in diameter. The worm slowly extends the tentacles often stopping during the process and if everything seems fine the tentacles are completely extended. As they fully emerge they open up into the distinctive head.

The worm doesn’t appreciate strong seawater currents because of the head. If the current is too strong the worm could withdraw back into the tube. It is best to locate the tube in an area where only slight to moderate currents exist.

If a worm is seen to be hanging listlessly out of the tube it is likely to be dying.

When the tube with the worm within is first introduced to the aquarium the proper acclimatization technique should be applied. During this period it is best to ensure the tube is not exposed to air at all. Once the worm is ready for transfer the tube can be placed securely between rocks being careful not to crush it, when the worm is active it should adjust any faulty anchorage. Place the worm as said in an area of light to moderate currents, and lower down on the reef particularly if the lighting is powerful. The worm hasn’t any need for lighting as corals have. A worm that is positioned in bright light could be slow to appear until it is accustomed to it. It is reported that the worms do not like high temperatures – a top temperature of 76 deg F is sometimes quoted, though I kept one at 77 deg F for a long time.

Sometimes an aquarist can be alarmed as the worm drops its crown of tentacles. This could have been caused by stress produced by too high a temperature, excessive and sudden seawater currents, too large a change in seawater specific gravity or harassment. The first three are easily avoided. Harassment is avoided by ensuring that only suitable tank mates are present. Many common reef fish, such as damsels, dwarf angels etc could nibble at the worm’s tentacles. There are more that could cause a problem. Fish such as the copper-band butterfly (Chelmon rostratus) should be avoided. The best fish to keep with the tubeworm are small dottybacks, fairy baslets, gobies, blennies and the like. The worm can disappear into its tube at a terrific speed thus avoiding trouble, but repeated occurrences of this lead to stress. Once any problem has been corrected leave the worm alone. It could take a longish period to re-appear, and they are capable of re-growing a crown.

The tube worm feeds on very small plankton in the wild. In the aquarium once the worm has been given time to settle and is displaying its full crown of tentacles it can be target fed. Using a small syringe-like device, a small amount of fine filter-feeder food can be ejected ‘upstream’ and allowed to drift over the tentacles. If necessary seawater movement pumps can be temporarily turned off though this should not be necessary. It is best not to squirt the food straight at the tentacles or it is likely the worm will withdraw them believing danger is present. In an aquarium where there are many other filter feeders the food shouldn’t go to waste and the seawater quality shouldn’t be affected.

Looking at the suggested fish companions for the worm it seems the ideal home would be a nano aquarium. In these small systems it is usual to keep smaller inoffensive fish. The worm can successfully be kept in a large system subject to the other inhabitants, which means a lot of discipline could need to be applied by the aquarist.

The feather duster worm is a different and very interesting addition to a captive reef. Below is a short video.

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Nudibranchs

The wild reefs are home to some pretty weird creatures and some of these creatures can be really attractive. The nudibranchs fall into this category, to me anyway.

On the wild reef many creatures have a niche for the supply of food. Some fish will just cruise along devouring their type of food, the usual example given are surgeons which often move in shoals eating algae. There’s a fish that farms algae and will aggressively defend the area from interlopers such as surgeons, though faced with a large shoal it has little chance. Some life forms are predators, others omnivorous. Whatever food is available, there’s something there to eat it, which is Nature’s balance.

Nudibranchs are the same; they have a food niche too. The food supply for all nudibranchs is not the same, most will predate on a particular type. Unfortunately for the reef aquarist, this food is often a type of coral.

Many aquarists check corals and coral rocks when they are purchased to try to ensure, as far as possible, that there aren’t any unwanted organisms. What are usually in mind are those weeds of the reef aquarium, aiptasia, and similar growths. It is possible that a nudibranch could be found.

I recall that many years ago I obtained a soft coral from my LFS, complete with rock. A general check was made of the coral and rock but nothing was seen to make me suspicious. A while later, maybe a couple of days to a week, I noticed the coral seemed to be unhappy and reducing in size. What made me examine it again along with its rock I don’t know but this is what I did. Underneath the rock in a crevice were two yellow nudibranchs. I removed them from the aquarium and placed them into a bowl which was floated in the aquarium. Attempts to identify the type of nudibranch failed. I took them to the LFS but they died.

The two nudibranchs I found will have been predators of that particular coral, which is why they were imported with it. If they had been left the coral would quite probably have been completely eaten, or been so badly mauled that it would have died. At that point it would have been death for the nudibranchs as there wasn’t any other coral of the type is the aquarium. That is why they died at the LFS, there wasn’t any food for them.

It is understandable therefore why nudibranchs are not a common feature of reef aquariums. There are very few aquarists who would be prepared to feed corals to them, no matter how beautiful the creature might be.

Many of these creatures have colouration which reasonably matches their prey, a defence against being predated upon themselves and making them more difficult to spot. Others have bright colours to warn that they are distasteful or dangerous to eat.

It isn’t just corals that could be the prey item for nudibranchs; some eat worms, fish eggs, mollusks etc. It is clear that all of them present a very difficult maintenance problem for the aquarist.

Nudibranchs (pronounced ‘nude – i – branks’ by the way) are really fascinating and strange creatures possessing different beautiful colouration. It is a great pity that they are not suitable for the captive reef. If they were, I for one would keep a couple.

The link provides just a few pictures of these creatures, there are many more types. Click on individual pictures to enlarge them.

http://www.poppe-images.com/images/search_results.php?keyword_mh=nudibranch&x=67&y=9

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Sponges

Everyone knows what a sponge is; they go in the bath or shower and are great for washing. They can appear or be placed in the marine aquarium as well, though they’ll look different!

Living sponges vary in size from very small, 1″ (circa 2.5cm) or so, to huge, 18″ (circa 45.75cm) or so in diameter. There are many different ones, the total numbering 9000 plus*. The sponge is not a single celled organism but multi. They are always stationary and meet success or failure in that one position. In a similar way to soft corals, the sponge holds its shape by means of calcium spicules, though some are silica which divides sponges into calcareous or siliceous types. Different types can be found from very shallow to very deep seawater.

Sponges feed by drawing seawater in and filtering out nutrients. Once the filtration is complete the seawater is ejected with any waste. This is a continuous process.

Sponges are fairly common in retailers and come in various colours and shapes. The shape usually indicates the area where the sponge originated, flat encrusting types originally living in high water flow and taller wider ones offering more resistance to flow coming from quieter areas. Sponges are sometimes found on coral rocks when the aquarist acquires a new coral. They could also be growing on live rock, perhaps unseen as they are hidden from view.

Some sponges seem to be hardy, these being the encrusting types which can be found on living rock and coral rock. They often survive without specific feeding and are welcome.

The larger, more upright and brightly coloured sponges are more difficult. When on the captive reef they without doubt add bright colour and shape, and can be a real temptation to an aquarist. The aquarist should resist the impulse to buy, unless he/she has experience enough to maintain corals successfully, that is maintaining them long term in a healthy and growing condition. This at least gives an indication of husbandry abilities. Sponges are sensitive to declining seawater quality.

If a sponge is bought, it must not be exposed to the air at any time. Transfer into the home aquarium should take time allowing the seawater to equalize. The aquarist should not touch the sponge but maneuver it by the attached stone. This makes the point that there should be an attached stone; a purchase shouldn’t be made without one. On no account place a sponge on or into sand, it will die.

Position in the aquarium is very important. Reef aquariums use very bright lighting for the sake of the corals and this could lead to some encrusting and other algae. Algae are one of the enemies of sponges. Therefore they should be positioned in a dimly lit area, under an overhang perhaps, or low down where light is reduced. The position should also have gentle seawater flow.

The major problem with sponges is feeding them. Nutrient levels in reef systems are low, with efficient protein skimming and routine seawater changing. It is very unlikely that there will be sufficient food matter to sustain a sponge. I don’t know if a sponge is able to make use of dissolved organic matter (DOM) but placing the protein skimmer on a timer and running it for half the usual period may be useful? A close watch would need to be kept on seawater quality in case corals objected. Perhaps the way to feed a sponge with the best hope of success is to use a pipette with very fine foodstuffs, such as the foods commercially available targeted at filter feeding corals and fan worms. The corals and fan worms will also benefit and hopefully the sponge will obtain nutrients. This feeding will place an additional strain on the bio-filter as it is likely not all the food will be consumed. Again, a watch will be needed to ensure there isn’t excessive deterioration of seawater quality.

Sponges are food for some livestock. There are fish that eat them and a good example is the rock beauty angelfish (Holocanthus tricolor). Other angelfish and butterflyfish are a danger to them. There are more, including some snails and urchins. So it is essential, as always, to check compatibility with existing livestock before purchase.

The sponge I remember was purchased because of its lovely bright orange colour. It was properly attached to a rock and was shaped like a lollipop, about 5″ (circa 12.75cm) tall. The sponge was introduced properly and carefully positioned.

A demand was certainly placed on that virtue of marine aquarists, patience. This was required when feeding took place – a commercial filter feeding food was used. Great care was taken to ensure a small cloud of food surrounded the sponge once, sometimes twice a day. Seawater quality didn’t deteriorate, I assume because the aquarium had other filter feeders. I didn’t reduce the period the protein skimmer ran; it was left on full time. Perhaps I should have experimented with that.

The sponge didn’t grow or deteriorate. It maintained full colour and shape for about 12 months. Then a little grey was noticed, and this was seen to be very slowly spreading. The sponge was removed from the aquarium, as I was afraid of sudden failure and pollution.

If an attempt is to be made in keeping a sponge purchased from a retailer, then it is suggested that notes are kept on the techniques used from the very beginning, including introduction to the aquarium, positioning, seawater quality and particularly feeding. If reasonably successful then let your local club or internet forum know about the procedures used.

The link gives pages of sponge pictures.

http://www.poppe-images.com/images/search_results.php?keyword_mh=sponges&x=65&y=10

(* Reference: Marine Aquarist Manual Comprehensive Edition. Dr. P. V. Loiselle & Hans A. Baensch)

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Cuttlefish

Usually seen in public aquariums, cuttlefish are likely to draw plenty of ‘oohs’ and ‘aahs’ from onlookers as they swim with their unusual long undulating horizontal fins. This reaction is particularly likely if the cuttlefish displays, sending waves of colour down the body with a rippling effect. They are also able to move by jet propulsion in the same way as an octopus.

The cuttlefish can be partly known to bird keepers, particularly those with budgerigars and similar. It is the cuttlefish bone that is used as it is a good source of calcium and also the birds seem to enjoy pecking at it.

Cuttlefish live in various areas of the world and can be large, 19″ (circa 48cm) or more, to small, 1½” (circa 4cm). Therefore, at least in most home aquariums, the larger ones are not suitable.

The colour displays that have been mentioned are achieved with the aid of chromatophores which are located in the skin. They are controlled by muscles and can activate with little delay allowing waves of colour to flow quickly across the body. It is reported that these colour patterns are a means of communication, indicating excitement, fear and also involved in mating.

Cuttlefish are predators and will continue their natural practices in the aquarium. Clearly prey is subject to the size of the cuttlefish, and includes crabs, shrimps, small fish, snails and even on occasion other cuttlefish. They have eight arms with two more that can be very quickly extended to grab prey.

Suitably sized cuttlefish could be considered suitable for the captive reef aquarium. Unfortunately there are two reasons why this is not so. The first is the lighting that is needed on reef aquariums to ensure the health and growth of the corals. This lighting is strong and can be a bank of fluorescent tubes to a halide system. Cuttlefish do not like this brightness. This may be because of their natural habitat situation and also perhaps because their eyes are well developed, possibly more so than any other invertebrate (other than in their own family group). The pupil takes a similar shape to a ‘W’ and can distinguish colour. Anyway, light levels in a reef system are too high, cuttlefish prefer medium to low light. The second reason is their predatory nature. Very often in a reef system there are small shrimps and/or crabs present and these will be a prey target, which is not going to please the aquarist. Further, many aquarists try to maintain high seawater quality by not having too many fish in their reef system, and one of the ways of achieving this is to house a restricted number of small fish. Again, it is likely that these fish will become a target.

It is possible to keep cuttlefish in two ways: in a species only aquarium or in a fish only aquarium. There will not be a problem with lighting as two fluorescents are sufficient, preferably arranged with electric timers into a ‘dawn/dusk’ sequence. If it is to be a species only type with more than one cuttlefish they should not be very different in size or there could be trouble. Mixing different types is also suspect and should be avoided. So ‘same species similar size’ is the guideline. The best and safest way, unless there is a lot of confidence, is to have one specimen – they are usually solitary in nature. If using a fish only system is being considered then the same comments about shrimps, snails, crabs and small fish apply, and in addition there should not be any larger fish that are aggressive or predatory by nature. In other words neither fish nor cuttlefish should be attractive as food to, or subject to aggression from the other.

As with most sea creatures the cuttlefish requires somewhere that is secure, such as a cave or the like. Rockwork will normally provide this but attention is needed during construction to ensure the cuttlefish is not too large to make use of the hideaway(s). The macro algae Caulerpa can be grown in the aquarium as well, which will enhance the aquascape and also be beneficial to seawater quality.

If keeping a cuttlefish is being considered, then the first requisite is that the aquarist is able to maintain successfully a fish only or captive reef aquarium. In other words, there should be experience in the maintenance of high seawater quality and healthy livestock. When a cuttlefish is located in a retailer it is important to have the creature correctly identified so that a check can be made on its eventual size (they grow quickly) for aquarium size consideration and also its temperature requirements (some cuttlefish require cooler seawater than is normal in a tropical marine system). It is also worthwhile seeing them fed, which will give the aquarist confidence and also the same food can be used at least to start. Cuttlefish will usually take to defrosted foods such as larger shrimp and fish.

Keeping a cuttlefish on its own or with suitable tank mates is more unusual than fish only and captive reef systems. It is possible, if there is the space, to have a captive reef and a cuttlefish in adjacent systems, perhaps interlinked for filtration purposes (subject to temperature considerations already mentioned). What a display! It goes without saying that maintenance, including routine seawater changes is required. Properly looked after, a cuttlefish can be expected to live to around three years or so, maybe more.

http://www.markspencer.com.au/image_library.php?q_search=Cuttlefish&q_file=tq_cuttlefish

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Sea Urchins

Anyone who has been barefoot in the sea and has stepped accidentally on a sharp spined sea urchin is likely to remember the experience. The spines are often needle sharp (there are variations) and some are equipped with poison glands.

Sea urchins are a good addition to reef aquariums, and also to fish only systems provided there aren’t any fish, such as triggers and puffers, that will do them harm. There should not be large hermit or ordinary crabs, lobsters or predatory snails in the aquarium either. It is not necessary to keep just one specimen of urchin, or the same type, though space restrictions and food supply mean usually one, or maybe two in a large system. They are considered safe with ordinary snails, shrimps and the like, and also corals. Sea stars and brittle stars are normally safe also, though some care has to be taken that the stars are not predatory. Urchins tend generally to move about at night, and during the day find a crevice or hole which affords them good protection. Having a sea urchin makes the overall picture more natural.

Sea urchins require good seawater quality or they may lose their spines and eventually die. They also require good seawater movement. Good seawater quality and movement is a requirement for the marine aquarium anyway so this should not be a problem.

Having enough food for the urchin is usually the main concern. For most algae is needed and in a marine aquarium this can be in short supply, in fact the aquarist probably ensures a low algae presence by if necessary having snails etc present which keep it low. Without algae the urchin will last a while but its demise is inevitable. The choice is to provide algae or not have an urchin. Some aquarists meet the problem by having a few marine safe flat stones available. They allow algae to develop on these stones in a very shallow small separate tank and then they are placed in the aquarium for the urchin. If the stones are used half and half then a continuous supply of food should be available. The other alternative is to reduce or not have any competition for algae in the aquarium though a watch is still needed to ensure there is enough.

There is clearly a requirement to check the space available in the aquarium taking into account the length of the urchin’s spines and the well-being of other livestock, for example the needed swimming space for fish. This usually will not present a problem.

When an urchin is purchased great care is required that seawater is not lost during the journey home because of a punctured bag. When being acclimatized to the home seawater, as with shrimps and sea stars, a fairly long period is needed preferably using the drip method. When the urchin is released it should not be permitted to come into contact with the air.

Urchins come in different sizes with short blunt spines to long sharp ones. The urchins I kept were black long-spined ones, generally known as ‘hatpin’ urchins. Though the retailer couldn’t give the proper name for them, research strongly suggested that they were Diadema setosum.
As these urchins have stinging spines care had to be taken when carrying out maintenance with a hand in the aquarium, but nothing untoward occurred because unlike say a lion fish, the urchins were in one place. They certainly added interest, increased the diversity of the livestock, and at the same time controlled algae (unfortunately it is reported that they are unlikely to touch green hair algae). I no longer have an aquarium large enough to allow an urchin to be present, or there would be one.

http://www.goldenstateimages.com/GSI_search.php?srch=sea%20urchin&op=ex

The link will give some idea of the colour and diversity of sea urchins.

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The Porcelain Crab

Crabs can be helpful or not in the aquarium. Some of the larger crabs are not required as they blunder about causing damage and disruption. Others¸ such as some of the hermit crabs, are colourful, interesting and at the same time perform a useful job scavenging which assists in keeping the system clean.

Another interesting crab is the porcelain. This term is often thought to refer to one crab but this is incorrect, they are multiple. Their size is not a problem as they achieve around ¾” to 1¼”. There’s another two good reasons besides their size which makes them particularly interesting to marine aquarists. First, they are very colourful. Second, they usually reside in the tentacles of an anemone, or more unlikely down underneath it. So they are similar in that respect to clownfish.

Porcelain crabs come under various common names depending on which one it is. To take one in particular the common name is ‘dotted anemone crab’, or sometimes the general ‘porcelain crab’. The proper name is a tongue twisting Neopetrolisthes ohshimai.

http://www.geodia.com/gallery2/main.php?g2_view=keyalbum.KeywordAlbum&g2_keyword=crab&g2_itemId=132

They are best kept in a reef system, obviously with an anemone. Anemones such as those inhabited by clownfish are appropriate. Though one or two of this type of crab are able to defend their home against clownfish, this one is likely to lose out and it is best if the aquarist makes the choice – clownfish or crab. They are both suitable for inclusion with an anemone. It is best that one crab is kept as two of the same sex will fight.* If it is known that two are a pair then fine.

In a high quality habitat they are hardy, but it would be best for the aquarist to gain experience and feel confident about aquarium general maintenance including seawater quality before proceeding. This is not so much for the sake of the crab – experience is required for the sake of the anemone as, at least in my opinion, though I note quite a few others of experience agree, an anemone is not the ideal starter for a beginner. If an anemone and crab are to be kept, it should be remembered that the anemone requires the proper lighting, though this is likely to be present in a coral reef aquarium.

Feeding the crab is not difficult. The crab is a filter feeder and to facilitate this method the crab is able to spread hair-like fan structures into the seawater. So to feed them the aquarist could target liquidized filter type foods over them. This needn’t worry aquarists however, as the crabs will also take small pieces of de-frosted food such as lance fish, shrimp etc. The crab will not require much food though feeding should be fairly regular, and any extra food the crab ignores will probably be caught by the anemone, which in turn requires feeding with the same kind of food in larger pieces but less often.

When considering livestock for an anemone, clownfish of various types are probably the choice of most aquarists. If a crab such as that described is chosen then the interest is just as high and the sight of the two life forms co-existing just as fascinating.

(*Ref: Marine Atlas. Helmut Debelius & Hans A Baensch)

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Tube Anemones

Tube anemones (Cerianthus sp) are fairly commonly seen in local fish shops (LFS’s). They are different and very attractive. They remind me a little of ‘feather dusters’ in how they live, and also of some fireworks in appearance. The ‘pretty’ fireworks that is, where colourful flames and sparks exit the tube a little way before curving over downwards. There are around 50 tube anemone species in the world.

In the aquarium they should prove to be generally hardy – the usual demands for a quality environment are required. The area in which they are located should not have strong seawater movement because of the long tentacles – it is better if it is fairly weak. The lighting that falls on the anemone should not be strong, but moderate to weak. There is another essential requirement and that is sand for them to bury into. The sand depth should be in the region of 3½” to 4½” (circa 9cm to 11.5cm), though deeper sand does no harm. The sand should be coarse and from coral. Those who do not want a decorative sand bed (the depths given are deeper than the normal decorative 1″ to 2″) could consider using a marine safe plastic box full of sand. The edges of the box would need to spread 2″ to 3 beyond the anemone’s tube edge. This could solve the potential for a dirty sand bed. A deep sand bed (DSB) is constructed of very fine sand and is not really suitable.

The anemone has a long tube which is made up of secreted mucus and sand. It extends down into the sand and forms a home and anchor for the anemone. As the tube is quite slender and pointed, it would be possible for it to come out of the sand, so the anemone can create an expanded tube or bulb at the bottom, which prevents this.

It has been reported that if the aquarist does not want sand in the aquarium a plastic tube is sometimes successful. The plastic should be marine safe and a little wider than the anemone, ensuring that the length is more than adequate. The tube can be placed in the aquarium – between rocks for example – where it will not visually intrude and the anemone put into it. Any plastic showing should be covered in encrusting algae growth fairly quickly and the anemone should hopefully be secure and healthy.

The anemone will be on full display when waiting for food capture. If a threat is perceived the anemone will disappear into its tube at very high speed.

As with other anemones, the tube anemones have defensive/offensive weapons. These are the nematocysts, or stingers, that lie curled like spring loaded barbed harpoons until released. They carry venom and this could cause problems if the aquarist does not exercise sufficient care.

The anemones must be located away from all other corals, colonial anemones etc as the sting is strong and could cause severe damage, even killing neighbours. The tentacles are long and therefore have a long reach. The anemones live singly in the wild and should be kept away from each other. Similarly, the aquarist should not put slow moving and less agile small fish in the aquarium, because if they come into contact with the anemone they are likely to become lunch or be badly stung.

Feeding is straightforward as the anemones will take small pieces of defrosted mussel, shrimp or similar – ensure the food is cut very small. Brine or mysis shrimp could also be target fed. The food just needs to fall among the tentacles. Do not overfeed, two perhaps three times a week is enough.

As with other types of livestock, if the needs of the tube anemone are met then the aquarist will be rewarded with a lovely and ‘different’ display.

The following link has photographs of these lovely anemones.

http://www.poppe-images.com/images/search_results.php?=Anemones&species=Cerianthus%20species%204

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