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.