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Though the saying goes that God favors the insects called Beetles (Order Coleoptera), having made so many species of them; I’d choose worms of various phyla in their stead. Indeed, some fifteen of thirty five phyla of living animals are worms according to Wiki. By some estimates there may be more species of "worms" than insects! Some groups are largely unknown to aquarists, others are considered undesirable (most flatworms, flukes, tapeworms…); and a few of benefit or use, including the subjects of this article.
Featherduster Worms; What Are They?
Featherdusters are members of the the segmented worms, phylum Annelida. This group includes the earthworms of fishing bait fame, these being classed as Oligochaetes (“few bristles”). Annelids also comprise the Polychaetes (“many bristles”) as many a hapless aquarists can relate to have been poked but good.
Polychaetes in turn are subdivided into two principal groups; the Errantia (“moving”), and Sedentaria (non-moving) species; comprising the Bristleworms and Featherduster Tubeworms respectively. All told there are some 12,000 or so described species of Polychaetes, with some species being VERY populous in places in the wild; some are used as human food, and in places there are species that make up a large percentage of pelagic filter feeding species diets; including large Manta Rays.
Polychaete Annelids are divided into two sub-classes:
Some Prominent Featherduster Species:
We’ll just mention the most common, hobbyist-available members of two families:
Family Sabellidae: Fanworms. Non-calcareous tubes produced that they live in, feed from. Fanworms are filter feeders that can retract their tentacular crowns when alerted. Often found attached to dead coral, or in sediment with part of tube exposed. Sabellids are collected most often in "polluted" harbors in mud/muck for the ornamental aquatics market. Many aquarists don't have similar environments (!) to house their Featherdusters... high nutrient, plankton levels... Another reason why these animals are best placed in "old" well-established systems, with ooze about, refugium sumps.
Family Serpulidae: Calcareous Tubeworms. Produce white, calcareous tubes, often with longitudinal ridges, thickening and, spines. The shape, size of cover (operculum) is often useful in determining species.
The tentacular crown of Featherduster worms is composed of feather like radioles. This is about all one can see that registers as “live” of these animals; and this structure serves several purposes; chiefly respiration and feeding. Such an important organ, and so exposed, the tentacles themselves are often the major source of injury and resultant reason for loss of the animal. There is more about this structure below in the section on feeding.
Featherdusters themselves get along with all other macroscopic reef life; not stinging, eating, chemically competing with any other biota. Unfortunately the reverse is not the same; with some fish groups in particular pulling on their heads at times. The usual suspects of Triggerfishes, large wrasses and big puffers or filefishes, along with some Butterflyfishes and Angels are suspects; and large clumsy animals like Eels and Urchins can work them woe as well as omnivorous crabs.
For soft bodied Sabellids, you should carefully examine the tube body to assure it is not torn or overly beat, especially around the open end. Hard-bodied (Serpulids) tubeworms should similarly be looked over for breaks in their tube channels. Beyond this is looking at soft tubed varieties to assure their blind end is intact (not torn open), and for calcareous species, that their covers and openings aren’t badly broken.
As with many invertebrate animal groups, it is important to avoid lifting these worms into the air, too-often causing air entrapment in their tubes. Instead, substrate dwelling and boring varieties should be bagged underwater.
A thick substrate (four or more inches) of small diameter calcareous material, with some organic inclusion is ideal for supporting Featherduster husbandry. This mix serves to bolster alkalinity as well as fostering the growth of useful food materials.
Water quality conditions should mimic a large-established reef system. Steady, near natural seawater specific gravity; tropical temperature; with a dearth, but still measurable nitrate and phosphate concentration.
Lighting is unimportant to where you situate your Featherdusters, but current and elevation are. Soft and hard-tube species (Sabellids) can be placed amongst rock et al. that will serve to anchor them, or buried in soft sand, embedded/boring tubeworms (Serpulids) are likewise best placed near the bottom (as opposed to higher in the water column) to benefit from higher concentration of foods there as well as dispersed circulation.
Water movement is critically important to these animals. Current should not be direct, but serve to move water under their crowns continuously. Experiment with your powerheads, internal pumps, discharges to ascertain whether this is so.
Featherduster worms are ciliary-suspension-mucus filter feeders on very small plankton, organic particles and bacteria. Though it’s hard to see without magnification each radiole (“feather”) of the crown of your Featherduster has a small central groove. This groove serves to sort and transport food items to the mouth, body of the worm further down the tube. Tiny particulate food items are caught up in sticky mucus the worm produces and transported down the collective food tube.
Understanding how the animal feeds is critical to your being able to feed it, keep it alive; as food particles are processed on the basis of size alone. Too big particles are flicked out before reaching this area, medium ones are incorporated into the tube itself, and suitably small materials are brushed along via cilia and ingested.
Like corals and other reef life, both carbohydrates and protein are required to keep life going. Providing these nutrients is not as easy as blasting a turkey baster or pouring in some liquid invertebrate food occasionally however. Tubeworms need nearly continuous quantities/densities of high quality phytoplankton, and bacteria sized particles (under two micrometers) to thrive. This food is taken from the underside of their tentacular feathers, not the top; and so needs to be in suspension, being circulated for them to take it up. I am a huge fan of the use of simple timers to temporarily suspend the operation of skimmers and mechanical filtration for tens of minutes after pulsing in particulate foods; allowing the recirculation system to move food items about without their immediate removal.
There are few systems with enough endogenous food material to support Featherduster worms; thus exogenous additions of cultures need to be supplied to assure adequate nutrition is supplied; otherwise these animals wane, shrink and die. Having a large, well-established refugium, better with mud/muck incorporated as a substrate is helpful, but you will still have to supply food from cultures outside the system.
Culture of these algae is really not a big deal; in fact, it can be quite fun. A starter population of Nannochloropsis et al. can be purchased from your LFS or ordered online from outfits like AlgaGen and LiveAquaria (.coms); this can be extended by simple culture in glass or plastic jars, made up seawater and dilute fertilizer addition.
Again, I warn you regarding the use of too-large food items, as well as “juice” of clams et al. and the too often “pollution in a bottle” which are commercial liquid/bottled invertebrate foods.
Sources of Mortality:
Though not much is known re pathogenic disease of Tubeworms, the reasons for their common loss are. Most all die too soon from a combination of trauma and starvation; both before (during collection, holding, shipping) and after landing in their ultimate and penultimate permanent settings.
So; what can you do to optimize your chances of returning and preserving health of these Sedentariate Polychaetes? It may not appear obvious, though it should, that picking out better specimens is the key to initial success, placing them in suitable circumstances, providing foods of use frequently and not introducing predators for longer-term.
Don’t lose your head! If your worm ceases to show its crown, or even loses it, don’t necessarily give it up as gone. These worms do regenerate this tentacular process, and at times this can take weeks to complete. I urge patience here. Through all-too common starvation these worms will toss off their crowns and regenerate successively smaller ones. As you might assume, this does not go on forever. A less large regenerated crown should serve notice that your animal is not getting sufficient nutrition.
Worms are not all gross! Featherdusters, Sedentariate Polychaetes are worthy specialized reef additions. Given sufficient outside-provided fodder they can live for years in captivity; starved; they might last a few months. Other than providing enough useful food, initially selecting good specimens and placing them in propitious circumstances is requisite for keeping these animals long-term.
Calfo, Anthony & Fenner, Robert, 2003. Reef Invertebrates. WetWebMedia
Hoff, Frank. & Terry Snell, 2007. Plankton Culture Manual, 6th ed. Florida Aqua Farms, Inc.
Shimek, Ron, 2008. The inside story on Featherdusters. Aquarium Fish Int’l. 6/08