The vast majority of worms will prove to be harmless or at the
predator of other small worms and pose no threat to the larger life
forms that we place in our tanks. Of course there are
exceptions. While some worms can grow large
and seem threatening they are in fact a vital part of the clean up
crew, taking care of unseen livestock deaths and left over food.
this clean up service that they provide that has led to some species
being labeled as fish killers as they are usually blamed for such
fish losses when they are seen on the corpse of the
fish doing their job of cleaning house.
In the hopes of saving you some confusion
as has happened to me quite a few times, I am showing a few examples of
the rear sections of various worm species as they can be quite easily
confused for the worm's head. A great many of the worms can be very
lengthy and it is very common to break the worms while trying
to remove them from rocks. Of course a good many times, I end up with
the wrong half. To further mislead you, the worm, even though broken in
half will still move its rear section in much the same manner as you
would expect the head to do. Add a few false eye spots and a worm's
hiney quickly becomes its head in appearance. Some species such as the
Nemertea have a suction cup like appendage as a hold fast for their
rear section which looks very much like a mouth and is often thrashed
about as you would expect a head to do, but in reality the rear
section is actually just in search of something to grasp onto.
( Ribbon Worms ) Generally, nemertines are carnivorous; most
feed on small invertebrates like crustaceans and annelids, but some
feed on the eggs of other invertebrates, and a few live inside the
mantle cavity of molluscs and feed on microbes filtered out by the
Below, an unknown species
Below, a Notospermus
Below, an unknown species
Below, various unknown species
called "Spoon worms", are considered close relatives of the Anellids
but lack the segmentation of the Anellids. Most species are found in
soft sediments forming burrows. The proboscis of the worm is usually
only part of the worm that we see as it gropes around for detritus and
other food particles on the substrates near its burrow.
The polynoids known commonly as "scale worms" are slow moving predators
which feed on small prey such as small crustaceans, echinoderms,
polychaetes, gastropods, sponges and hydroids in spite of their strong
jaws. They are famous for their commensal habits, some living
with asteroids, echinoids, holothorians, sea anemone, sea
and corals. They are known as scale-worms as their dorsal surface is
covered with enlarged scales or elytra which may be concealed by a
dense coating of setae. They are medium sized. They are secretive and
are mostly found occupying tight crevices beneath stones. Some species
are commensals in the burrows and tubes of other invertebrates or the
shells of hermit crabs.
Extended Jaw Details :
Below, a Harmothoinae sp.
Below: Unidentified Scaleworm
Below: A scaleworm of the Acoetidae
tubes much like the "featherdusters" do and is an active predator and
scavenger. Also a large worm, the specimen shown below was as thick as
my finger and at least four inches long.
- The Sigalionids are burrowing predators living in sand or
A few species inhabit tubes. Others have spinning glands and produce
numerous tough fibers incorporated into the tubes. They are common in
soft-bottoms. Being long-bodied and their scales being closely appended
to the bodies, they appear rather pentagonal. Also members of the
Species below is
a Euthalenessa oculata
- Cirratulids are deposit feeders which gather food from the sea bottom
by means of their palps. They are sluggish worms which bury themselves
below the surface of sea bottoms leaving only their gills and palps
visible. Some are free-living and inhabit tubes, while others are
capable of burrowing through corals, shell or rock. Hence, they occur
both in shallow water as well as deep sea. They inhabit mud flats or
muddy areas between rocks. They are usually orange or bright red and
are found among mussels and kelps. They are indirect deposit-feeders.
They have no proboscis as their food is collected by their palps and
carried to the prostomium.
Below: A hair worm hiding just under the
sand's surface extending its feeding palps.
WormsArticle #2 -
These animals, which are commonly called "peanut worms" because some
have the general shape of shelled peanuts, are not particularly well
studied. Only about 320 species have been formally described, all
marine and mostly from shallow waters. While some burrow into sand and
mud, others live in crevices in rocks, or in empty shells. Still others
bore into rock.
The Priapulida Worms -
The Priapulida, or Priapula are a small phylum (about 16 species known
to scientists) of normally small worm like animals. They range in
length from 0.5 mm for species of Tubuluchus to
around 200 mm for species of Priapulus. They occur
in most seas, both tropical and polar, at a variety of depths, from
shallow coastal waters to as far down as 7,200 meters. The name
Priapulida refers to the fact that the scientists who first named them
thought they looked like a human penis, however they look more like
some species of cacti and it would not be unreasonable to use the term
Cactus Worms as their common name. All known species are marine and
benthic (meaning they live in or on the sea floor).
THE "BRISTLE" WORMS
This is an extremely large
classification of worms, of which I will try to
post representatives of, within reason.
are what give the "bristle" worms their name. Each member of this
family comes armed in various rigid hair like structures that are used
for defensive means. Do not attempt to handle these worms
their bristles easily penetrate human skin, depending on the species
and your own personal reaction level, the resulting puncture can result
in anything from a mild irritation to being very pain full. Do not
attempt to rub them off as you will only drive the bristles in deeper.
Instead, soak the effected area in very warm vinegar until the bristles
dissolve. A thank you to David Lee for sacrificing his finger
the name of science!
- The phyllodocids are slender errant worms often brilliant green,
yellow or red. Most of them live in crevices and under stones. Active
predators of other small worms. The phyllodocids are common
shallow-water polychaetes commonly associated with hard substrates and
corals rather than mud and sand.
Amphinoids are also known as "fireworms"
and have calcareous
setae filled with poisonous secretions. When irritated, they erect
their sharp setae which break off at a touch releasing their poisonous
contents into the wound. Most species are found on corals, rocks and
other hard substrata covered with attached organisms. They swim well
and can be brilliantly colored. All but one species can be considered
harmless and are great scavengers.
The below pictured specimen is a Pherecardia striata,
also a member of the fireworms and is a scavenger.
Genus Pareurythoe , which has very
Eurythoe complanata -
most commonly found worm and is a harmless scavenger, a benefit to our
- The hesionids are active and
carnivorous. They are commonly found in hard substrates and
shallow water rarely in deep water and soft sediments. The larger
hesionids are carnivores feeding on polychaetes and other small
invertebrates. Some may be deposit-feeders, ingesting
Below, a Leocrates spp.
(member of the Hesionidae)
- Quote, Leslie Harris "There's been a lot
of debate about where these belong but traditionally they've been
considered polychaetes. The "legs" are parapodia; each one has a stout
hook (or a few) which enable them to hold onto their hosts which are
usually crinoids or other echinoderms. Some are external symbionts,
others are internal & can be found in galls or in the body."
The eunicids sometimes known as "rock worms" are mainly omnivores and
live largely on detritus. They may be scavengers, and are found mostly
in rocky habitats. Some species build tubes while others
into limestone. They are either errant or tubicolous frequently
inhabiting coral reefs, sands and muddy substrates. These are the most
commonly found worms that I encounter within live rock tunnel networks.
Some of the larger species, or those
that grow to
adult size in your aquarium may pose a threat to some sessile
invertebrates and possibly some types of coral species. I have at least
one large specimen in my aquarium and it has posed no threat to
Jaw extension , and a great visual clue as to why
you do not want this in your aquarium.
Below is a typical rock burrow that the larger
such as the one above, will fashion by "gluing" rocks together with a
mucus secretion. It is thought that these species account for new coral
reef habitats as they bring together smaller rocks, thus forming a
larger area that corals can settle upon, encrust and start the makings
of a new reef habitat.
The Syllidae -
The syllids are a large and diverse group of active worms which are
mostly found creeping over sponges, ascidians, hydroids, bryozoa and
algae or burrowing in the surface layers of silt and are common in
protected sandbanks. They pierce the skin of these sedentary animals
and pump out the juice. They are common in shallow water forms, and
tend to be numerous on hard substrates and soft-bottom sediments.
Species shown in the below three
photos is a member of the Amblyosyllis genus ( a Syllidae )
shown below is about 2mm in length, a very tiny worm yet its stripes
are still visible from a distance.
The Nereids (Quote,
Leslie Harris ) "Carnivores, predators, scavengers, detritivores,
omnivores, herbivores - pretty much every type of feeding except filter
feeding & parasitism occur in the family. Many species are
switch hitters. If a tasty pod is crawling by they'll grab it but if
not they'll eat mud & digest the attached bacteria, detritus,
The Lumbrinerids -
They are primarily soft bottom inhabitants, but can occur on hard
substrates. Some construct mucus tubes. They have a well-developed jaw
apparatus suitable for grasping food material. Most of them are
predaceous carnivores or scavengers.
( Predator of snails and clams )
- Oenonids are mostly large worms that burrow in
sand and mud, but a number of species are parasitic. They resemble
lumbrinerids in appearing earthworm-like, but can be distinguished from
them by the presence of a flattened head.
The Glycerids -
The glycerids burrow in sandy or muddy substrata by means of their
reversible proboscis. The purpose of burrow construction is
for prey capture. The glycerids detect the hydrostatic change within
the burrow when motile polychaetes or crustaceans move across the
burrow system and thus shoot out their proboscis and grab its
prey. They are mainly carnivorous.
- The capitellids commonly known as "lugworms" resemble the
earthworms and have similar habits. They burrow in various
grades of sandy mud inhabiting mucus-lined tubes. Their guts are filled
with inorganic matter along with organic matter.
The Dorvilleidae -
Members of this family are much smaller than most of the more
larger, visible families and pose no real threat to other life in our
aquariums. They will appear as very small white lines on the glass of
our aquariums and are very common. Each specimen that I have examined
under a microscope appears to be gut loaded with algae. While a good
many species are extremely small, there are of course much larger
species, some of which have been reported up to three inches long.
The species shown below is
about 1 mm in length and is in the genus group Ophryotrocha
The Spintheridae -
An ectoparasite of sponges. Extremely small and
to see when laying flat against its sponge prey. It does however leave
behind its tell tale damage as shown in the below photo. Very
similar in appearance to harmless Bryozoans.
The Swarmers "
Prior to segmented release of Epitoke
A swarming Phylodocid found within my aquarium at
It is less than 1 mm in length but still visible as being a worm.
An Ophelidae swarmer releasing
A Unicid full of eggs releasing them
A Syllid swarmer (epitoke) in the
genus. A male full of sperm, females carry their eggs on the
Another Syllid Epitoke
carrying away (green) eggs to be released as plankton.
A Spionid epitoke, a first find for me as I have
never seen a spionid outside of its tube.
Some polychaete species also form clear,
masses which may become coated with detritus, cyanobacteria. Usually
after a few days, the eggs will develop into worm larvae which are
released after the "bubble" has disintegrated.
Quote by Dr. Ron Shimek )
we usually mistake as another worm species can very well be a modified
version of a bottom dwelling worm specialized to swim in the water for
reproduction. There are number of types of swarmers (some are called
"epitokes," some "heteronereids"). In essence the two major strategies
used seem to be:
1) Some species (primarily in the group known as the syllids)
bud a whole specialized individual (a clone) off some portion of the
adult. That clone is modified in having no gut, super-sized eyes, and
super sized parapodia (lateral paddles). In these animals, the interior
of the worm is packed with fat and other food reserves. The definitive
adult deposits its fertilized eggs on the swarmer which then breaks off
and swims away. As it swims, it - of course - disperses to a new
habitat carrying the babies on it. Those babies develop through the
embryonic stages while attached to the swarmer/swimmer. When it finally
runs out of food (remember with no gut, it can't feed). It settles to
the bottom, and the, now, juvenile worms can strike out on their own.
2. Another type of swarmer is formed from the entire adult
which transforms itself into a swimmer in much the same manner as the
one above. However, in this case, the gut degenerates and the entire
inside space of the worm is filled with gametes (either sperm or eggs).
When the time is right, these worms (generally in the thousands to
bizillions) swarm to the surface and writhe around. In doing so, they
rupture and release eggs or sperm into the water. The gametes meet,
and... some time later a new worm settles out of the plankton.
3. A different rather intermediate version is seen in some of
the tropical eunicids (the palolo worms, where the worm buds
off a swarming portion filled with gametes. These portions swim up to
the surface as in the case above. However, here instead of the whole
worm committing suicide in an orgy of reproduction, only a portion of
the adult participates while the portion remaining at home in the
burrow regenerates and gets ready for next year. "
While any of the below listed worms are highly unlikely to
found as hitch hikers due to their very large size, I thought they
would at the least, be of interest.
The Enteropneust -
(Quote Dr. Ron Shimek) " Such
worms are relatively common in the sand flats around coral reefs, and
are one type of animal that seems to be impossible for reef aquarists
to get. They are animals that REALLY would help a sand bed in a reef
tank. They are burrowing sand swallowers and are an evolutionary
"half-way house" (aka "un-missing link") on the way to chordates
(we'uns) from some other, possibly, wormy ancestor. They have
(hundreds) of gill slits in the pharynx or throat that correspond to
the gill slits in the feeding region (branchial basket) of tunicates.
The gill slits also are homologous to the gill slits of fishes. They
are one of the few animals in marine ecosystems that actually could use
the iodine that most aquarists carelessly and foolishly dump into their
systems. " Note: This specimen is now residing within my
reef systems deep sand bed.
This specimen is
three feet long
of the tube worms are harmless and may show up in large numbers usually
in high flow areas such as found in our sumps and overflows as well as
on the landscaping and some types within the sand. There is only one
type of worm that I know of that we put in our tanks on purpose, the
large tube featherduster worms, these types do have specific care needs
so please take the time to research this animal. Tube worms can come in
a large variety of sizes as well as how they structure their tubes,
the tubes themselves can be in a variety of shapes as well, from tiny
tight circles, to large upright tubes as well as nothing more than a
burrow in the sand with its tube formed by cementing sand particles
together to brace the walls of the sand tubing. They can also be found
living in some of the larger pores of our live rock, again, forming
mucous lined tubings such as the spaghetti worm does. The largest
family of this type of worms are the feather dusters, of which I
will try to show a few examples of. In short, if it has a feathery
appendage sticking out of the end of a tube, it will be a feather
duster in general common name terms.
Tube in the sand formation