Red Tube Worm (Sabellastarte spectabilis)

A feathery filter feeder for the marine aquarium

The Red Tube Worm (Sabellastarte spectabilis) is a marine fan worm: a segmented polychaete in the family Sabellidae that lives in a tough, leathery tube and spreads a plume of branched, feathery tentacles into the water to feed and breathe. Wikipedia's account of the species also calls it the feather duster worm, feather duster or fan worm, places it in the tropical Indo-Pacific, and records the worm reaching 80 mm (8 cm) in length and 10–12 mm in width.

It suits a keeper who already runs, or is carefully building, a mature marine aquarium set up for invertebrates, and who wants a calm animal to watch rather than a fish that swims to the front of the glass. This worm never chases food. It stays in its tube and catches fine organic particles as they drift past its crown, so three decisions matter more than anything else: stable water, a secure place for the tube, and tank mates that leave the crown alone.

Because it is sessile, the worm cannot walk away from poor water or a troublesome neighbour the way a fish or shrimp might. Everything on this page is organised around that fact: the care tab covers feeding biology, water values, filtration, placement and arrival day, and the compatibility tab turns the same biology into a set of screening questions for any animal you plan to keep alongside it.

One worm per purchase, and the names it goes by

What arrives

Each purchase supplies one live Red Tube Worm in its tube. The soft body stays inside, and the crown of branched tentacles, which biologists call radioles, projects from the open end to form the plume you see in the aquarium. That plume is both the feeding surface and the breathing surface, so the way you handle, place and protect it shapes everything else on this page.

Sex is guaranteed only when the selected option explicitly states male or female. This Red Tube Worm listing has no sex-guaranteed option. Plan for it as one animal that settles into a single spot in the rockwork and stays there, so the choice of that spot is the most important decision you make on arrival day.

Why you may see another scientific name

You may see this worm sold as Sabellastarte indica. WoRMS, the World Register of Marine Species, records that name as unaccepted and gives the accepted name as Sabellastarte spectabilis (Grube, 1878), in the family Sabellidae within the order Sabellida. The naming has a tangled history: the worm appeared in Hawaii under the name Sabellastarte sanctijosephi, Hartman used S. punctata and S. indica in 1966, and a 2003 revision of the genus by Knight-Jones and Mackie concluded that S. spectabilis is the correct name. If an invoice or care book says Sabellastarte indica, it refers to the worm now accepted as S. spectabilis.

Colour, photographs and the trade name

Red Tube Worm is the trade name this animal is sold under rather than a promise about the shade of every crown. The species account describes the tentacles as striped in dark and pale brown bands and the body as buff with purple specks, and the photograph on this page shows a crown banded in tan and cream. Gallery images have been digitally enhanced to improve image quality. Natural colour, pattern, size and maturity can vary between live animals. Plan the display around the worm's needs rather than one exact colour.

If you are building an invertebrate display, the marine invertebrates we keep for reef aquariums are grouped together, so you can plan the rest of the aquarium in one place; run each candidate through the screening questions in the compatibility tab before it joins the worm.

How the crown feeds and breathes

Wikipedia describes S. spectabilis as a filter feeder, and the mechanism explains most of its care. Tiny hair-like cilia on the tentacles set up currents in the water. Organic particles are caught as they float past, then passed along mucus-filled grooves to the mouth. Larger particles that are not food are put to use as building material for the tube, and the same tentacles work as gills for gas exchange.

Three practical points follow from that biology:

• The crown does two jobs at once. Anything that nips, tears or keeps disturbing the plume interferes with feeding and breathing together, which is why tank-mate screening matters so much for this animal.
• Food has to come to it. The worm lives permanently in its tube and cannot move to find a meal, so whatever it eats must reach it in the water flowing around the crown.
• It complements your filter rather than replacing it. Aquarists value fan worms for removing organic particles and helping water quality, but one worm is a small living filter. Biological filtration, water changes and testing still carry the aquarium.

It also helps to be clear about what the worm is not. It is not a grazer that scrapes films from rock, a scavenger that tidies leftovers from the sand, or a hunter. Foods made for those feeding styles are of no use to it and simply add to the waste your filter has to process.

A body built for a sheltered life

Polychaetes are marine bristle worms with long bodies divided into many segments. Some roam, swim or burrow, while others, like this one, live permanently in tubes. The species account describes two long, slender palps and a four-lobed collar below the crown, with a tube covered in fine mud. The tube is the worm's armour and anchor, so a sound, undamaged tube sitting firmly in rock is the first thing to protect after arrival.

Build a stable marine system before it arrives

OATA's guide to setting up a marine aquarium starts with size: buy an aquarium as large as you reasonably can, because a larger volume of water is more stable and less prone to swings in temperature and pH than a small one. For an animal that cannot leave poor conditions, that stability is worth more than any single piece of equipment.

Reef or fish-only?

OATA separates fish-only aquariums from reef aquariums, which hold invertebrates such as corals, and suggests that a newcomer to marine keeping starts with a fish-only tank or a soft coral reef. A fish-only tank can later become a reef tank if the species are compatible, usually with extra equipment. A fan worm is an invertebrate, so it belongs in the invertebrate plan and the water values set out in the next section.

Where the aquarium stands

• Out of direct sunlight and away from sources of heat or draughts.
• On a flat, level surface or stand that can take the weight of the full aquarium indefinitely.
• Away from loud noise, vibration and sudden movement.

Water, salt and rock

OATA recommends reverse osmosis (RO) water for marine set-ups and calls it essential if you keep invertebrates, corals included, which covers this worm. RO water can be bought already salted or as fresh water to mix at home. Dissolve a specialised aquarium salt, never table salt, following the manufacturer's instructions; once the aquarium is running, mix and heat water for future water changes in a separate vessel so new water matches the aquarium before it goes in.

Rockwork, ideally living rock, gives fish a natural refuge and provides sites to place corals and other sessile invertebrates. OATA also recommends a layer of fine coral sand, washed in RO water before it is added. For this worm, the rock matters most: its tube needs a hole, crack or crevice where it can sit firmly, and planning that spot while you build the aquascape is far easier than forcing one in later.

Water values to hold steady

Keep the aquarium at 24–26°C, pH 8.0–8.2 and a salinity of 1.024–1.026 SG (32–35 ppt). These are OATA's broad guidance figures for home marine aquariums that hold invertebrates rather than a species-specific optimum, and they are the column to follow for a reef-dwelling fan worm.

Why not the fish-only figures?

OATA's fish-only column is wider: salinity 1.017–1.023 SG, 24–27°C and nitrate not exceeding 20 mg per litre. Those limits are set for fish. An invertebrate aquarium runs saltier and cleaner, so a system sitting near the bottom of the fish-only salinity range is a long way from where this worm should live. Bring the aquarium into the invertebrate column before the worm arrives, not afterwards.

Measuring and a worked example

OATA treats a hydrometer or refractometer for salinity, and test kits for regular water-quality checks, as core equipment. Ammonia and nitrite should both read zero before any livestock goes in and should stay there. Nitrate and phosphate tell you whether feeding and maintenance are in balance, which matters for a particle feeder that tempts you to add food to the open water.

Suppose your refractometer reads 1.022 SG and your nitrate test shows 15 mg per litre. Both would be acceptable in OATA's fish-only column, yet both sit outside the invertebrate column. Raise the salinity steadily with correctly mixed salt water and use water changes to bring nitrate into the 5–10 mg/l band, then re-test before ordering. If your aquarium will also hold hard corals, OATA adds that calcium and magnesium need monitoring too.

Mature the filter and add animals slowly

The nitrogen cycle in brief

The RSPCA's aquarium environment advice explains why filtration comes first. Animals release ammonia, which is toxic. A working biological filter lets beneficial bacteria grow, and those bacteria turn ammonia into nitrite, which is also toxic, and then into nitrate, which is safer. The RSPCA is clear that no fish should be kept without a well set up and maintained filter, and a filter-feeding worm, breathing through its crown in the same water, is no exception.

Letting a new system settle

OATA advises that once a marine aquarium is filled and at the correct salinity and temperature, it should be left for 24 to 48 hours so that any salt fully dissolves, the temperature settles and you can confirm the equipment works. If you run a skimmer, you may not see it remove any waste until livestock is present. That short settling period is only the start: the filter bacteria build up as animals and food are added, which is why a fan worm belongs in a system that is already carrying a steady load.

Stocking slowly

OATA explains that the beneficial bacteria must increase every time more animals go in and feeding increases. Overstocking, or stocking too quickly, can bring on what keepers call new tank syndrome, when there are not enough nitrifying bacteria to cope with the extra waste. The practical rule is simple:

1. Add one new animal or small group at a time.
2. Test ammonia and nitrite over the following days.
3. Add the next animal only while both still read zero.

For this worm, that means it should not be part of the first wave of livestock in a new aquarium. Let the first livestock establish the filter, confirm the invertebrate water values above hold steady, and then add the worm when the system has room for one more feeder.

Give the tube a secure, sheltered home

Wikipedia's habitat notes place this species in holes and cracks and among algae on reefs and rocky shores. It has been found growing in crevices in the coral Pocillopora meandrina, under boulders in still water, in holes in lava, in tidal pools and in channels exposed to heavy surf. Beyond its native range it has also been reported on pilings, floating docks and harbour walls in Hawaii.

Those are wild records rather than aquarium targets, but they point to two useful conclusions. First, the worm anchors its tube in a protected hole, crack or crevice, so give it one. Second, it lives in everything from still water to heavy surf, so there is no single water speed to copy from the wild. In the aquarium, aim for a spot where water keeps carrying fine particles past the crown and the plume can spread without touching rock or other animals.

Choosing the spot

• A crevice in stable rockwork where the base of the tube is protected and cannot roll or be knocked loose.
• Clear water around the plume, so the spread tentacles do not rest against rock, corals or neighbouring animals.
• Moving water, not a dead corner. A filter feeder relies on particles floating past, so avoid pockets where debris settles and nothing moves.
• Away from busy sand. OATA notes that some fish filter the sand to feed or sleep under it at night; a tube placed in their working area can be dislodged or buried.
• Where you can see it. Daily observation is the best early warning you have, so choose a place visible from the front of the aquarium.

Handling the tube

Move the worm by its tube rather than by the crown, and keep handling to the minimum needed to place it. The tentacles are its gills, so keep the time it spends out of water as short as you can. Settle the tube so it is supported along its length, then leave it alone. Wikipedia notes that the worm can regenerate body parts after damage, but regrowth is a recovery to hope for, not a reason to take risks with the crown.

Feed the water column without fouling it

Its natural food is fine organic matter suspended in the water, caught on the crown as it drifts past. In an aquarium, the aim is to keep a light supply of very fine particles in the water around the worm without letting uneaten food build up and pollute the system.

What to offer

Choose foods fine enough to stay suspended, sold for filter-feeding marine invertebrates, rather than foods made to sink for fish or bottom feeders. Release a small amount into the water upstream of the crown so the current carries it past, then watch where the food travels and whether any of it settles on rock or sand.

How much

Start with small amounts and let your test results decide whether to increase them. OATA links rising feeding directly to the load on the filter bacteria, and the RSPCA's explanation of the nitrogen cycle shows where excess food ends up: as ammonia, then nitrite, then nitrate. Food that the worm does not catch becomes waste for the whole aquarium.

Reading the signs

The last row is the one to aim for. A stable routine, with test results that stay inside the invertebrate column, is better for a filter feeder than frequent changes in food or quantity.

Arrival day and the first weeks

Everything is hand-packed by our team: the worm is bagged in pure oxygen inside an insulated poly box, with a heat pack when the weather calls for it, and carried by a licensed live-animal courier. You receive an email with the tracking number and your confirmed delivery date, so you know when to be in. Someone must be at the address to receive the parcel, because live animals cannot be left unattended. The full terms are on our delivery and Live Arrival Guarantee page.

Arrival steps

1. Be at the delivery address to receive the parcel.
2. Start a continuous unboxing video before anything is opened: show the parcel still sealed with the outer box visible, open it in one take, and keep filming until the worm is visible inside its sealed bag.
3. Inspect the worm the same day the parcel arrives.
4. Float the bag in the aquarium for 20–30 minutes before releasing, and acclimatise slowly.
5. Never pour the bag water into your aquarium; lift the worm out by its tube and place it in the spot you prepared.
6. If anything has gone wrong, contact us the same day, WhatsApp is fastest, with your order number and the unboxing video, and we will arrange a replacement or refund.

Checks before the parcel comes

OATA's advice for any new arrival applies here too. Confirm that the worm suits the animals you already keep and that ammonia and nitrite read zero. OATA also recommends switching off the aquarium lights and taking the bag out of its outer wrappings carefully, avoiding exposure to bright light. OATA notes that fish are easily stressed by bright lights, extreme temperatures, noise and movement, and the same gentle handling costs nothing for an invertebrate.

The first weeks

Once the worm is in place, leave it undisturbed and watch rather than adjust. Each day, note whether the plume is spread into the water, whether the tube is still firmly seated, and whether any tank mate is paying attention to it. Pair those notes with water tests: a change in the worm alongside rising nitrite points to water quality, while a change with clean readings points to placement or neighbours. If the crown is damaged, the worm can regrow body parts, so keep conditions stable and the water clean while it recovers. If you are unsure what you are seeing, contact us with a photograph and your latest test results.

Reproduction and regrowth in the wild

Wikipedia's biology notes describe a worm with more than one way to reproduce. These are natural history rather than a breeding plan for the home aquarium, but they explain some of what you may notice and why the animal copes with damage better than you might expect.

• Asexual reproduction. The worm can reproduce by fragmentation, and it can regenerate body parts after being damaged.
• Sexual reproduction. Most worms are either male or female. Gametes mature inside the body cavity and are released into the water column, where fertilisation takes place outside the body.
• Changing sex. Some specimens, particularly larger ones, carry both male and female gametes, and a study in Hawaii concluded that this fits sequential hermaphroditism.
• Larvae. After a short time in the plankton, the trochophore larvae settle out and grow into adult worms.

What this means for a keeper

Because fertilisation happens in open water and the larvae drift in the plankton, a single worm in a filtered aquarium is not a breeding project, and nothing about keeping it depends on sex. The ability to regrow damaged parts is the more useful fact day to day: it gives an injured worm a chance, provided the water stays clean and whatever caused the damage is removed. Treat that resilience as a safety margin, and keep crown-damaging tank mates out of the plan from the start.

Screen every tank mate around a sessile worm

Add the worm only to a mature marine aquarium kept to invertebrate water standards, and before any fish or invertebrate joins it, confirm that animal will not pick at, bite or dislodge a tube-dwelling filter feeder. That single rule covers most of the risk.

The worm itself is no threat to anything in the aquarium: it feeds by catching organic particles from the water and stays in its tube. The danger runs the other way. Its crown is soft, it cannot retreat to another part of the tank, and it depends on that crown for both feeding and breathing.

Four questions for every candidate

1. Does it eat or pick at invertebrates? Any animal that feeds on sessile invertebrates, or habitually nibbles feathery or soft tissue, puts the crown at risk.
2. Does it dig, sift or move rock? OATA notes that some fish filter the sand to feed or sleep under it at night. Animals that work the substrate or shift rockwork can dislodge or bury a tube.
3. Is there room around the plume? Place other sessile animals far enough away that nothing rests against the spread tentacles.
4. Does it share the same water plan? OATA reminds keepers that species prefer different water types, flow rates and temperatures. A companion that needs fish-only conditions is a poor match for an aquarium run to the invertebrate column.

When a neighbour may be the problem

Once you identify a culprit, separate it from the worm. Repeated damage leaves the crown little chance to regrow, however good the water is.

OATA's wider advice is to check that any new animal is compatible with those you already own before buying, and to ask your retailer about the species you have in mind. If a candidate fails any of the four questions, leave it out of the plan.

Fitting the worm into a reef display

OATA describes reef aquariums as holding invertebrates such as corals, and the invertebrate water values in the care tab are written for exactly that kind of system. In the wild, Wikipedia records this worm among algae and in crevices of the coral Pocillopora meandrina. That is a wild association rather than proof that any particular coral makes a good neighbour, so apply the screening questions to corals and other sessile animals as well as to fish.

Planning order

1. Build the rockwork with the worm's crevice planned in, with open water in front of it.
2. Mature the filter and bring the water into the invertebrate column.
3. Add livestock slowly, testing ammonia and nitrite between additions.
4. Introduce the worm once the system is steady, then add later animals only after screening them against the worm.

If you are converting a fish-only aquarium, OATA notes that the change is possible when the species are compatible, usually with additional equipment. Screen the existing fish first: an established fish that fails the questions above rules the worm out of that aquarium.

A worked conversion

Say you keep a mature fish-only aquarium at 1.021 SG with nitrate at 18 mg per litre, and one of the fish sifts the sand. That system is within OATA's fish-only column but not ready for the worm. Before ordering, you would decide whether the sand-sifter and the worm can share the aquarium at all, make every batch of new salt water from RO water, bring salinity into 1.024–1.026 SG and nitrate into 5–10 mg/l, and build a crevice high in the rockwork, well away from the sand the fish works. Only when all of that holds steady does the worm join.

Questions keepers ask

How big does a Red Tube Worm get?

Wikipedia records this worm reaching 80 mm (8 cm) in length and 10–12 mm in width. It lives inside a tough, leathery tube, with a plume of banded, feathery tentacles spreading from the open end.

What size aquarium does it need?

Choose a mature marine aquarium set up for invertebrates and as large as you can reasonably keep, because OATA advises that a larger volume of water stays more stable in temperature and pH. Plan a sheltered crevice in the rockwork with open, moving water in front of the plume.

Is a Red Tube Worm suitable for beginners?

OATA suggests that newcomers to marine keeping start with a fish-only tank or a soft coral reef and move on as they gain experience. This worm fits once your filter is mature and you can hold OATA's invertebrate guidance of 24–26°C, pH 8.0–8.2 and 1.024–1.026 SG steadily.

What does it eat?

It is a filter feeder: cilia on its tentacles draw water past the crown, and organic particles are caught as they float by and carried to the mouth. Offer fine foods that stay suspended, in small amounts, and let your nitrate and phosphate readings guide the quantity.

What temperature and pH does a Red Tube Worm need?

Keep it at 24–26°C and pH 8.0–8.2, with salinity at 1.024–1.026 SG, ammonia and nitrite at zero and nitrate at 5–10 mg/l. These are OATA's broad guidance for marine aquariums with invertebrates, not a species-specific optimum.

Is it aggressive, or does it nip fins?

No. It stays in its tube and feeds only on organic particles caught from the water, so it does not chase or nip other animals. Its own soft, feathery crown is the part that needs protecting.

What kinds of animals can a Red Tube Worm live with?

OATA describes reef aquariums as holding invertebrates such as corals, and in the wild this worm has been recorded among algae and in coral crevices. Screen every fish or invertebrate first and leave out any animal that picks at, bites or dislodges sessile invertebrates.

How does a Red Tube Worm arrive alive in the UK?

Start a continuous unboxing video while the parcel is still sealed, inspect the worm the same day, then float the bag for 20–30 minutes before releasing; the Live Arrival Guarantee needs that video. It travels hand-bagged in pure oxygen in an insulated poly box, carried by a licensed live-animal courier.

Sources

• World Register of Marine Species (WoRMS): Sabellastarte spectabilis for the accepted scientific name, its unaccepted synonym and the family placement.
• Wikipedia: Sabellastarte spectabilis for common names, description, length, native range, habitat records, filter feeding and reproduction.
• Ornamental Aquatic Trade Association: how to set up and look after a marine aquarium for set-up, water values, stocking and new-arrival advice.
• RSPCA: aquarium environment for filtration and the nitrogen cycle.