People sometimes ask me about the proper care of the beautiful feather duster worms, that have been traded as novelty items since before the age of reef tanks properly began. The available information is always vague, to say the least; it always includes the sad truth that these beautiful and fascinating organisms, do not usually last long in aquariums.
A number of species of Sabellastarte sp. are reaching retailers; at the point of sale they tend to be traded with descriptive labels, such as 'giant' or 'fireworks'. If a species is identified at all, it is probably (and inaccurately?) Sabellastarte magnifica, which is from the Caribbean Sea and neighboring waters. Although true S. magnifica are traded, feather dusters from other oceans cannot be this species.
As a child I was interested to see feather duster worms in marine aquaria - there was nothing like that in our tropical tanks! But they were not kept well and tended to shed their crowns and die. Such problems resulted because these animals were not granted appropriate water flow or food items.
Sabellastarte sp. belong to a clade of annelid worms called canalipalpates, that possess no teeth or jaws. Rather they possess mouthparts that are known as a 'branchial crown'. This organ is not only the feeding apparatus of the fanworm, but also how it breathes. The 'feathwr duster' of Sabellastarte sp. is in fact their mouth, and they produce and open it in order to feed and breathe in the water current. As these worms live in a hard tube that they secrete around their soft bodies, they are considered sedentary annelids; they retreat their vulnerable crown into the tube no avoid it being nibbled at
Sabellastarte and it's relatives selectively filter particles from the surrounding water. They reject some of the entrapped items as debris, but choose others as beneficial for building their tubes, or of course simply eat edible material. They are considered unfussy as to what they consume, beyond particle size, as the literature reports them consuming unicellular algae, floating filaments of green algae, and zooplankton including tiny larvae.
Misinformation about these worms might suggest they will simply consume fish waste or uneaten foods. Rather, the bulk of their natural diets is phytoplankton, and this should be respected in our aquarium settings. As with other suspension feeders, feather dusters always fo better when they are housed in long established reef aquaria, which have good microbiota for their consumption.
Another problem is flow, for feather duster worms rely on the ambient water flow to bring them both food and oxygen, as well as to carry away their bodily wastes. Yet very strong currents can also damage these delicate animals. In the wild they are common in habitats such as bays and harbors, which are protected from strong wave action; elsewhere, they are found in microhabitats of low flow in the crevices of the reef. Therefore in the aquarium, the animal should be placed where surrounding flow visibly but very gently moves the crown of the worm when it extends.
Unlike for example sea anemones, feather duster worms do not possess venomous stings. Accordingly they are prone to be nipped at by passing fishes in the wild, and also in the aquarium. For this reason it is important that any cohabiting fish and crustaceans, should not be of the common habit, of biting sessile animals as a part of their natural diet. Suitable fishes might include planktivores that feed in the water column, or strict algae and detritus feeders.
It is actually sad to think that do many of these worms, abd the related koko worms of the genus Protula, have died in our tanks. In the days before 'reefing' these annelids were imported as living novelty items, because they are eye-catching and simply very 'different'. But they do not possess very difficult care requirements and, if the flow and nutrition are correct, they can be expected to flourish in reef tanks.
Different species of Sabellastarte grow yo different dimensions, and the largest members of this genus can grow yo have crowns that are 10 centimeters or four inches across Other species in the genus will stay smaller. They should probably best be placed into a sandbed but with their crown nut buried at its base, and the substrate should not be disturbed. The feather duster worms will take appropriately sized particles as building materials for the tubes that they secrete; the tubes are not a part of their own body, but a house that they legitimately build for themselves.
