Having fully retired to the
Philippine islands in 2004, I have had the unique opportunity to
further my own understanding and experience with the keeping of reef
aquaria, I have also been able to observe and learn first hand of the
many reef habitats and the life they contain. Such observations do come
with a risk in that I am also privy to the pressures faced by
the reefs on a day to day basis.
While some may blame our hobby for the decline of
animals due to
their capture and collection, there are a great many more destructive
habits and reasons for such decline. We can not of course, be put fully
to blame. But blame there is. I would be deceiving both you and me if I
were to state otherwise. Our hobby does have an effect on wild stock.
Such effects can only be negated by either stopping the collection of
all animals for the aquarium trade, or by us, as hobbyists, learning to
reduce our impact by the breeding
and rearing of captive stock when ever possible.
While the breeding of a great many species is
still beyond our
ability, nevertheless great strides have been made with a number of
species. Many coral, fish and invertebrate species are now commonly
reproducing in our aquariums. This is often to the credit of dedicated
hobbyists who are not content with the keeping of a few pets, but take
great joy in being able to provide those pets with the environment they
need to thrive and reproduce. Each and every member of this hobby is
capable of contributing to the knowledge
that allows themselves and others to take a species one step closer to
relieving the pressures our hobby can place upon the wild stocks.
While the majority of our hobby has to work from
the end of the
supply chain, I have the chance to work at the beginning of it. When I
am able to breed a specific species, I can then supply the local
exporter here with captive bred stock thus reducing or even eliminating
the exporter's need to collect that species from the wild
in the first place. This is my goal with the Harlequin Shrimp.
A Mated Pair,
Female is on the left, Male is on the right.
a doubt, the Harlequin Shrimp is one of the most elegant looking of the
shrimp species. It is no wonder why they are fast becoming popular as
pets. What I, as I am sure others find endearing about this shrimp is
in the apparent
closeness that mated pairs seem to share. Never, at any time, have I
seen a mated pair any further apart than an inch or two, at most. I
realize that this closeness is strictly to ensure a mate is always
nearby, but it is endearing none the less. Even when busy with their
own starfish, they will still remain side by side. These are very
gentle, easy going shrimp and will not threaten any other life in the
aquarium, with the exception of most starfish of course.
A note on Hymenocera
Picta : There seems to be
some confusion as to whether or not there are two distinct species of
this shrimp, the Elegans and the Picta.
Those who believe that there are not two different species often place
the elegans in with the picta.
I believe this is backwards and it is the picta
that should be placed in with the elegans. this is
simply because it is much more likely that the picta,
a central pacific (Hawaii) inhabitant, migrated or was swept by the
currents into those locals from the indo-pacific regions, which happens
to be the center of all reef diversity. I will not be at all surprised
if the picta turns out to be nothing more than a
color variation of the elegans and not a distinct,
separate species. As such, all the information provided in this article
can and does equally apply to the picta.
As with any marine species, water quality plays
an important role
in ensuring they remain healthy. Being an invertebrate, shrimp do not
tolerate anything less than reef grade water. If you can provide
water quality, you should have no trouble at all in being able to keep
your pet healthy and free of problems.
I prefer to keep my shrimp in their own
dedicated tank for
breeding purposes and observation. Therefore, I have put my shrimp
breeding system in front of my reef aquarium's
sump in order to facilitate water changes between the two tanks. As
long as the reef aquarium has reef grade water quality this arrangement
makes such a task very easy to accomplish and avoids any acclimation
If you must use a synthetic salt mix,
prepare the water at least
two days in advance of it being needed to allow it to age and become
properly mixed and aerated. Prior to use,ensure the new waters pH,
salinity and temperature match the water the shrimp are in. They are
easily affected by sudden changes and any water changes done with
synthetic mixes should be gradual, doing no more than ten to twenty
percent at a time, allowing a day between changes. When using my reef
aquarium's water, I have changed seventy five percent of their water
with no ill effects. Again, I must stress the importance of water
quality and not shocking the shrimp with rapid synthetic water changes.
These factors alone account for many shrimp deaths.
Being a timid species, it is also vital
to ensure their aquarium
is safe from predators or other animals that may harass them. Even a
fast moving fish passing by can cause these shrimp stress and they may
go into hiding and be unable to properly eat. For breeding purposes, I
feel a tank dedicated to a single mated pair is a must. As pets, taking
the simple precautions of having pump inlets protected and any possible
predators removed will make keeping this species a simple matter. With
good water quality, a peaceful environment and the proper food, you
should have no trouble in maintaining this species for a good many
A Male (left)
and Female (right) Mated Pair
This may not be easy for those that do not have access to
a variety of starfish. While I have the luxury of being able to collect
any starfish myself. For those of you that have to purchase starfish in
order to feed these shrimp, you may wish to use some of the more
prolific starfish such as the common Asterina species found commonly
hitch hiking in on purchased live rock. Over the course of time, I have
collected a variety of starfish species in order to determine which are
found palatable or not, to the shrimp.
If starfish are not available, in a pinch you can
adding a small sea urchin. It has been reported that these shrimp have
been known to eat the tube feet of sea urchins when starfish become
scarce. I have tried small sea urchins, but my shrimp paid them no
interest. I like to ensure that the shrimp have at least one decent
meal each week, although they are capable of going three to four weeks
without food. By keeping them well fed you will increase your chances
of the female producing a great many more eggs.
In order to avoid having to feed an
entire starfish at one time
it is a common practice to cut off one of the starfishes arms and feed
that to the shrimp while keeping the remainder of the starfish in
another aquarium. In due time, the starfish will regenerate its lost
arm. By keeping a number of starfish, you can rotate through the
starfish, having them each donate an arm when required. I find this
method of feeding to not only be less wasteful of starfish, it also
allows the shrimp to feed right away. It can take a few days for the
shrimp to actually break through a starfish in order to get at the
internal parts that they eat.
Please do not add more than one starfish
or starfish arm at each
feeding. It is very common for the shrimp to combine their feeding
efforts onto one starfish or starfish arm. Leaving the second starfish
to crawl off, possibly wounded or having a second arm decay within the
When feeding the shrimp break off and release a great many
the starfishes spicules. These are microscopic structures that give the
starfish its bodily support. Such spicules resemble microscopic needles
which, I am sure, would be an irritant to corals. To reduce any chance
of coral irritation when keeping harlequin shrimp in a reef aquarium, I
would suggest using a micron filter to try and reduce the number of
free floating spicules. Or, better yet keep your shrimp in a dedicated
tank of their own.
Once the feeding shrimp kill the starfish
I do not allow it to
remain in the aquarium longer than three to four days to avoid having
the starfish pollute the aquarium water. Once a live starfish has been
introduced to the aquarium, I take it out after two
weeks whether or not the shrimp are done with it.
While being fed, I perform daily water
changes and continue to
do so for a few days after the starfish carcass has been removed. A
week later, I will feed the shrimp again. This is done to ensure the
shrimp have enough energy for breeding, spawning and molting. If the
shrimp are being kept solely as pets, then I would feed them at least
once every two to four weeks. The times I have noted as to how long a
starfish will last and/or degrade are simply averages. It will vary
based on the size and species of starfish and how the shrimp happen to
dismember the starfish.
: Listed below are the starfish species that I have found to be a good
food source for the harlequin shrimp. I have tried numerous brittle
star species but the shrimp seem to be afraid of these and will not eat
them. I believe this is because brittle starfish are fast moving and as
they rapidly try to find a hiding place the shrimp are intimidated.
If you do decide to try other starfish
than the Linkia species,
keep in mind that many of these starfish are predators of corals and
other invertebrates. Should they escape the clutches of the harlequin
shrimp, they could pose a real threat to your other reef inhabitants.
This is yet another good reason to keep these shrimp in a dedicated
aquarium of their own.
When deciding upon a species of starfish
to be used with the
"sacrificial" arm method of feeding, I would chose the Protoreastors
(Choc.Chip Stars) since they are easy to maintain and feed upon readily
obtained seafood meats such as clams and oysters. Such a steady, meaty
diet will ensure that the starfish can regrow its lost limb(s) much
faster than other starfish groups. Species such as Linkias may not find
their dietary needs being met and would most likely take a great deal
longer to replace lost limbs, if they survive long term to begin with.
Crown of Thorns
Depending upon their health and quality of diet, the harlequin
shrimp will molt an average of once each month. Prior to molting you
can see the exoskeleton looking like an old dirty "skin". This seems to
cause the shrimp great irritation just prior to molting. They will
constantly pick at themselves as if trying to speed up the process by
making the exoskeleton more loose by their tugging at it.
As shrimp and other crustaceans grow,
their exoskeleton does not
grow with them and they must form a new exoskeleton to match their new
size. During the period between molts they also repair themselves. If
an antennae, leg or claw is lost new ones will grow and become evident
after molting. It may take more than one molting period to fully repair
any damaged or lost limbs. Keeping the shrimp well fed and in water of
good quality will ensure they have the nutrient resources to complete
such tasks. Even with such care, things can still go wrong for the
shrimp during the repair process and the actual molting event. It is
during molting that most shrimp losses occur.
I have noted that over the course of a
few months, a new pair
will synchronize their molting. My pairs seem to do their molting
within the same day of each other. This could be coincidental but is
most likely done to facilitate mating. I am not in the habit of dosing
my shrimp's aquarium with iodine and have not observed any ill effects
from not doing so. I feel that the belief that shrimp somehow need
iodine in the water in order to properly molt is unfounded. Keeping the
water at the same calcium and alkalinity levels as you would for a
coral reef aquarium should provide for the needs of the shrimp.
Once molting has been completed, do not
be surprised if the
shrimp disappear out of sight for an extended period of time. They are
extremely vulnerable (soft) to predators and they know it. After a few
hours, their new exoskeleton will harden and they should make a
reappearance. If not, you may try enticing them out with a starfish.
Looking a bit haggard just
prior to molting
out of the old exoskeleton
This only occurs directly after the female has broadcast her spawn.
Once all of the larvae have hatched, it is normal for her to molt the
next day. Once she has molted she is immediately ready to form a new
clutch of eggs, but first needs the male's contribution as the eggs are
fertilized as they pass by the deposited spermatophores. The male will
lift the female's tail and turn himself onto his back and join with the
female. It is at this time that the male applies spermatophores or
sperm sacs close to the opening of the female's genital duct. The sperm
sacs are shed from a pair of holes at the base of the last legs and the
eggs from holes on the third legs.
Within 24 hours of mating, the female
eggs which become fertilized as they pass by the spermatophores. The
female holds the fertilized eggs in a brood chamber under the abdomen
"glued" onto hairs of the pleopods. The eggs remain attached to the
female during incubation. When mating is completed, the male will
"piggy back" on the female to guard her against the advances of other
males. He will continue to be protective of her in this manner until
she forms a new clutch of eggs. Once the new clutch is formed the
female will reject the advances of all males, including her mate.
The male guarding
Male lifting the
female to gain access
The actual mating event
When compared to other shrimp species, the harlequin shrimp seems to
come with some extra parts, or parts that are not easily identified as
to what they are due to their flamboyant structuring. Trying to find,
let alone determine, what the various head and claw structures are can
be a bit of a challenge as the shrimp tends to shield itself, making
its smaller details difficult to see.
eyes appear to be well developed and allow the shrimp to make out
details, if the object is close enough. From a distance, they most
likely can only make out movement and the differences between light and
The mouth is not readily visible since their food particles
extremely small, hence no need for a large opening. The mouth can be
seen as the vertical slit shown in the photo.
Maxillipeds are appendages modified to function as mouth parts in some
shrimp species. I have not seen the Harlequin shrimp use them as such.
In this species they may serve more as a means to recognize friend from
foe as mated pairs often touch with their maxillae as if taste testing
The Pereiopods :
All shrimp have five pairs of Pereiopods ( legs ), most of
serve specialized or multiple purposes. Usually only the last three
pairs are used for walking, while the first two pairs are modified to
serve as claws for gathering food and as weaponry.
of first pereiopods, which rules out their use to inject vemon as some
believe is possible
The first Pereiopods, or feeding claws are unique with the
harlequin shrimp due to their specialized use. These are what the
shrimp uses to break into the starfish by nipping away small bits of
the starfish's external structure (skin?) until an open wound is made
large enough to insert the feeding claws. The shrimp then switches to
using them to tear away small pieces of the starfish's innards and
transfer them to the mouth.
Pereiopods, which are armed with a claw (chela
referred to as
The claws of the harlequin shrimp do not appear to serve any purpose
other than as offensive and defensive weapons. They are used
offensively to "pinch" an opponent or defensively as a shield when
under attack or feeling threatened. I have also noticed that when
feeding, the shrimp will use its large claws as a shield to hide its
feeding activity. This is most likely done to prevent drawing attention
to the movements of feeding and to protect its vulnerable mouth parts.
The third, fourth and fifth pairs of
Pereiopods are primarily
used for walking. The pereiopods also bear the sexual organs, which are
the third pereiopod in the females and the fifth pereiopod in the males.
FAQ - "
keep more than one pair in an aquarium?
" This would of course depend upon the size of the aquarium.
Being that these shrimp are very territorial and defend their mates, I
would only attempt a second pair in very large aquariums. Even then,
there is no guarantee that one pair or the other will not seek out and
attack their rivals. The males may also attempt to move in on the other
males female. I would not risk it myself.
I keep other species of shrimp with the Harlequins?
" Again, in larger aquariums that give each species its own
territory, I see no problem in keeping other commonly kept species of
decorative shrimp in with the harlequins. If there is a squabble over
territory, or if threatened, the harlequins are quite capable of
warding off any would be aggressor. This of course does not mean that
species such as the mantis and some pistol shrimp species are
" Is there an
acceptable food alternative for harlequin shrimp?
" No, not that I am aware of. Starfish are their only food
source. This factor alone should be a large consideration when deciding
if you are going to keep this species of shrimp or not. Some would
argue, and with good cause, that the keeping of harlequin shrimp places
an unnecessary strain on wild starfish populations. This is a moral
decision that I will leave up to you.
harlequin shrimp inject the starfish with a toxin to make it stay still
" No, there are no shrimp capable of envenomation. What
is that as the starfish falls under the grasp of the shrimp it simply
withdraws and remains still while under attack. As long as the shrimp
remains on the starfish and constantly picks at it, the starfish will
feel constantly under attack and remain withdrawn, unwilling to move.
Should the shrimp move off of the starfish and the starfish has not
been gravely wounded it will try to slowly crawl away. Should
starfish die and start to decay, the shrimp will move off of the
starfish. This should be your clue to remove the corpse. I also believe
that this is the one reason that harlequin shrimp do not attempt to
capture and eat the fast moving brittle starfish, simply because
brittle starfish do not withdraw and remain still. They put up a fight
of sorts and do not ever give up in trying to get away. This along with
their quick actions makes it impossible for the shrimp to keep the
brittle starfish under control. If harlequin shrimp were
of toxin use, then the brittle starfish would be just as vulnerable
and readily eaten as are other starfish species. For
of this information, please see this thread within Dr. Ron
MY ATTEMPTS TO DATE
In the hopes that what little I
accomplished so far will encourage others, I am making what
little progress I have had available online. I hope that you will also
attempt to raise your larvae and contribute any knowledge gained. None
of my previous attempts have seen any of the larvae reach the
settlement stage which I believe was simply due to water quality
issues. Hopefully I am past that point now and will continue with my
I must state right up front
that I am not in this for financial gain. You will find that the costs
and limitations of a home based breeding program will ensure you might,
at best, break even. But, don't count on it. Such breeding
attempts, in my opinion, should not be based on possible monetary gains
but as a chance for you to contribute to the hobby and take just a
little more pressure off of the wild stocks. A labor of love if you
In order to collect the larvae
hatch out, it is important to provide the adults with a dedicated tank
of their own. This can be anything from a ten gallon tank on down to
just a couple of gallons. Trying to collect all of the newly hatched
larvae from a large reef aquarium and all of its filtration will be
nearly impossible. Keeping small dedicated systems ensures you have at
least a fighting chance of noticing a hatch and being able to collect
enough of the larvae to make such an endeavor worthwhile.
To be fair, I must warn you
that this endeavor will be one of trial and error, with a good bit of
luck tossed in as well. One little mistake made along the way can cause
you to start all over again. But if you stick with it, you will
hopefully master this art and contribute to the knowledge base of
breeding and raising a marine species. Just having a batch of larvae
hatch out is enough to get me excited while looking forward to the
upcoming challenges. Yes, it is a challenge, and one that takes a good
bit of dedication to see it through. Get lazy one time, and you can
lose all the larvae very quickly. Thankfully, the shrimp breed often
enough that you will not have long to wait before you get another
Since my wife and I live in a small apartment, I found it
necessary to limit the size and scope of my breeding program by
designing a simple, compartmented kreisel design. Such a design allows
me to keep the station near my reef aquarium. As I stated earlier, I
use water from my reef for partial water changes to the breeding
station. Of course, you can use prepared salt mixes when doing the
daily partial water changes, but I prefer to use the water from my reef
aquarium as it makes the chore a very simple matter. If you do the
same, please ensure that your reef aquarium's water is of very high
quality. Any problems with phosphate and nitrate levels will have a
very detrimental effect on the larvae.
Since the station sits directly
of my reef aquariums sump, its only a matter of siphoning out a quart
or two from the station's compartments and refilling the station
directly from the sump. I then pour the station's old water back into
the sump which allows my reef aquarium to cleanse the old water. Not
only is avoiding mixing or collecting new salt water a time saver, it
also prevents any shock issues to the larvae and adult shrimp with new
water. This is where keeping the station scaled down in size comes in
handy since everything that is done to it involves small amounts.
I can not stress enough the
having a kreisel to rear the larvae. I have tried the air line in the
corner method. It becomes a real pain trying to find just the right
amount of bubble flow that will do the least damage and yet still
provide the proper aeration. No matter how slow of an air flow I
provide, the larvae are all lost by the second day due to having been
pulled into the bubble flow and damaged. I quickly grew tired of this
and experienced the total loss of a good number of hatches.
A kreisel can be bought or custom
any number of shops that work with custom acrylic fabrication. Since I
do not have that luxury in the Philippines it was up to me to build my
own. I found this quite easy to do. It required nothing more than a few
small pieces of acrylic, a bit of nylon stocking and a very small
powerhead with a length of hose that fits the outlet of the powerhead.
As you can see in the above photo, it was
not all that difficult to build. I had a custom aquarium built at a
glass shop that allowed for it to be placed in front of my reef tank's
sump. The dimensions used to built this system were for space saving
measures only and can of course be modified to fit your needs.
For the kreisel section, I used a
acrylic (had to buy a picture frame and cut it up) to form another
divider to create a pump and aeration area as well as having a screen
mesh installed. There were only two concerns kept in mind while
building this system, water quality and getting the proper circular
water motion within the kreisel section.
the mesh screen, you can try other material such as micron filters, but
I have found that cutting up a simple pair of lady's nylon stockings
works very well. I do not have a clogging issue and the larvae and
their copepod food can not pass through. The baffles shown are simply
small pieces of acrylic cut to fit snuggly and siliconed into place.
The powerhead was the smallest one that I could find (50 liter per
hour). You do not need a strong flow to create a gentle circular
current within the kreisel section.
For me, the beauty of this system is in
providing the proper
circular flow, while aerating the water with no concerns of killing the
larvae. This is done by building an air bubble trap in the back corner
of the pump compartment. By doing so, you can run all the aeration you
want with no worries. This confines the bubbles to the back corner,
avoids making a mess with salt water spray and keeps the bubbles from
the pump intake so there are no micro bubbles in the kreisel to damage
The above photo shows what the bubble trap that I created
like. By the way, this design is very handy for use on all small
aquariums that are aerated by air stones. For the details on how to
construct one, please see my Air Bubble Trap Web page.
Once you have your flow adjusted within the kreisel, and with a clean
screening mesh, I mark the water levels as noted in the above photo,
between the kreisel and filtration compartments to allow for the
monitoring of any evaporation. Such marks also makes it easy to see
when the screening mesh is becoming clogged up and needs cleaning. I
also write the hatch dates of the larvae within the kreisel as a means
of keeping tabs on their age.
The Kreisel fully cycled and in action. Note the sandbed in
filtration compartment, this was added to provide the required
biofiltration. Also, the light was moved well above the Kreisel to
prevent the bulb from heating the water. As long as the light is
positioned above the kreisel section, the larvae remain suspended in
the water and are not attracted to any one point.
A few tips if you decide to build a similar kreisel design
You can use any sized aquarium that you wish, although the
smaller ones such as I have used, are easier to work with. Their needed
water changes do not require a great deal of water, maybe a gallon at
Get a small powerhead with a flow valve since even with such
small powerhead, I have to turn the flow valve to just above the shut
off point to get a nice gentle flow going.
hole for the mesh screening as large as you can, this allows a much
slower flow to go through the mesh which prevents any larvae from being
pinned against the mesh by a higher flow rate. A small opening would
force the water to blast through it.
divider piece a bit lower than the top of the tank. If the mesh should
become clogged, the water can overflow the top of the divider back into
the pump area and avoid having the tank overflow and flood the house.
- Keep the compartments
relatively small, this
not only makes water changes less of a chore, but also helps in keeping
the larvae fed. I do not have to put a great number of copepods in with
the larvae to get the concentrations needed to ensure that they have
enough nearby food to catch. In a larger set up, it would take far more
copepods to create the same live food concentration.
Paint the outside back and left
side (kreisel side) black as the larvae will be attracted to any light
sources. Since they are going to do this no matter what you do, I
prefer to take advantage of that fact and restrict the light to being
only able to enter the kreisel opposite of where the screen mesh is.
This keeps those larvae that do get out of the circular flow away from
mesh and the need to get themselves off of it.
If you do use nylon
stocking material, be sure that when gluing it into place with
silicone, that you stretch the material tightly or it will stretch out
too much when in use. I also used some old aquarium trim (the blue
shown above) to pin down the stocking material with silicone and to
give it a framed look.
If the nylon screen
should start to become clogged, as will be evident by the higher water
level within the kreisel section, I simply use the siphon hose when
doing the daily partial water change to clean the kreisel side of the
screen. I prefer to use a length of airline tubing as the siphon hose,
its small diameter gives me greater control of what is, and is not
being siphoned out.
The pump compartment can also be used to provide biological
filtration by placing a shallow layer of sand or even some bioballs
within it. I would not use rock rubble as you would most likely face a
problem with debris building up underneath it all. With just a shallow
sand bed, it can be lightly vacuumed if ever needed, which I have never
had to do. Anything such as bioballs, should be easy to remove to gain
access to the floor of the pump chamber if cleaning is ever needed. I
also leave any algae growing on the glass as well. This not only
provides a bit of nutrient uptake but also gives any errant copepods a
place to live and multiply, hopefully surviving the journey through the
pump to end up as larvae food in the kreisel section.
Quite a number of
copepods can be maintained in the kreisel section by simply feeding
them a small amount of phytoplankton each day. Not only will this keep
the copepods alive and enriched for the shrimp larvae, it also
encourages the breeding of the copepods which can and will hatch out in
the kreisel section. While being small enough to pass through the
kreisel's screen, it appears to do the copepod larvae (naupalii) no
harm to make the journey through the pump section as I continue to find
a great many naupalii within the water at all times. The phytoplankton
will also help with water quality by up taking nutrients as it
This is normally quite easy since in the wild mated pairs are commonly
collected and kept together to be shipped out and sold as mated pairs.
Obtaining such a pair should be a simple matter of doing an online
search or having your local store order a pair for you. If you only
need a single individual, should one of the pair die, then the store
should be able to distinguish between the sexes, allowing you to order
a male or female replacement. If the store employees do not know how to
sex the harlequin shrimp, you can describe how to do so (described
below) or you can shop elsewhere if you are not comfortable with their
ability to do so.
If you do find yourself with a single
another male or female is usually quite easy since a lone harlequin
shrimp is usually very receptive to gaining a mate. To lessen any
risks, I would place the new shrimp at the far end of the tank and
allow them to find each other in their own good time. Tossing the new
shrimp right down in front of the established shrimp may instigate a
defensive strike just out of fear. Such strikes could cause unnecessary
damage to the shrimp.
you know what to look for it is fairly easy to tell the sexes apart.
When mature, the female will appear obviously larger than the male. The
best, and most accurate method is by getting a look under their
abdomens. The male's abdomen will be clear or yellowish in color,
lacking any blue spots. The female will have obvious blue spots under
her abdomen and usually the very telling egg mass as well.
While in the process of laying a new clutch of eggs, the female may go
into hiding for a day or two. I have never seen the actual egg laying
take place, yet am always happy to see her return with a new clutch of
eggs. While the female is carrying eggs, she will paddle her pleopods
quite often in order to aerate the eggs. She will also spend a good
deal of time picking at the eggs, which I assume is done to keep them
clean of any debris and to remove any unfertilized eggs.
Depending upon the temperature of the water, the eggs usually develop
and hatch out within 2 to 4 weeks. Since I keep my shrimp's water in
the low to mid 80's, and the adults fed well, two weeks is usually the
period between spawning for my pair. I usually start checking for
larvae in the parents' tank ten days after noticing a new clutch. I do
this by placing a small pen light against the aquarium after the room
has been dark for a few hours and look for free swimming larvae. Just
as other crustaceans and their larvae are attracted to light, so are
the shrimp larvae. This makes their collection much easier as well.
Females Egg Mass
When the female senses that the time is near, she will climb to the
highest point of the rock work during the middle of the night, usually
between 1:00 – 3:00 AM. I say usually, because I have had
broadcast their spawn at 11AM, with all the lights on, as well. During
her broadcasting, she will briskly fan her abdominal pleopods casting
her newly hatched young out into the currents.
Thus begins the pelagic life of the shrimp larvae. In the wild for a
number of weeks the larvae will drift about on the ocean currents as
part of the plankton. They will feed upon their fellow plankton
members, mostly the copepods that make up the bulk of the zooplankton.
When you first notice a new hatch, you will of course want to remove
them to the larval rearing tank. Prior to moving the larvae, you should
drain out half of the water from the larval rearing tank and fill it
back up using the water from the parents' tank to avoid any shock or
Collecting the larvae can be accomplished by simply holding a small pen
light to the side of the parent's tank and scooping up the larvae with
a small cup or vial. Since my adult pairs are kept in small tanks, it
is quite easy for me to use a white plastic spoon and gather up as many
as I can in each spoonful. The white background of the spoon makes
seeing the larvae very easy. Do not be tempted to use a siphon hose to
collect the larvae. While it may be faster and easier, I feel it poses
too much risk of damaging the fragile larvae.
You can also devise an automated larvae collection system which is
detailed in April Kirkendoll's book "How to raise and train your
Peppermint Shrimp". I highly recommend this book as most of the
information she provides can be used or adapted for use with harlequin
and other shrimp species. I personally found it a great source of
information to get started with.
Another method used involves moving the female to the larval rearing
kreisel or tank to broadcast her spawn. If the kreisel has a slow flow
the female should not have to be kept contained in any manner within
the kreisel or larval rearing tank as she is quite easy to capture and
This method is most likely the best, since you are not stressing the
larvae or damaging them in any manner through your collection efforts.
Once you have noted the normal time period between spawning, you should
move the female at least two to three days prior to her estimated date
of spawning. Since harlequin shrimp are not known to consume their own
young, the precautions taken with other species of shrimp are not
needed. Once she appears to have finished spawning, simply catch her
using a small cup (so as not to damage her with netting material) and
return her to the adults' tank.
This will take some daily maintenance on your part. Your most immediate
task will involve ensuring that their water quality remains pristine.
The only way you will be able to do so is by performing small water
changes each and every day. Skip a day, and you risk losing your
larvae. Ammonia and nitrites are very deadly to the larvae. These water
changes will also be used to siphon out any and all debris that may
accumulate. I use a foot long piece of rigid tubing that is attached to
a length of airline tubing. The smaller diameter allows greater control
over what you are siphoning out and poses less of a risk of tossing the
baby out with the bathwater, as would happen with larger diameter hoses.
If you can avoid putting your hands into
the water, do so. This
will prevent less of a contamination risk. Before you throw away the
water you siphoned out, it is a good idea to inspect the water for any
hapless larva that got siphoned out. I simply use a plastic spoon to
scoop up the larvae and return them to their tank.
With this tank being near filterless, I
must stress again the
importance of doing water changes and siphoning out any debris on a
daily basis. Without much of a biological filter established,
will not take much debris to quickly pollute the water. This is all
extremely important for the first few weeks of this tank being set up.
After three or four weeks, the bacterial and algae film on the glass
should help in maintaining water quality and you may be able to skip a
day or two depending on how much you feed the tank. This is yet another
area that you will have to use your judgment and experience to gauge
whether you can get away with taking a day off or not.
After having read a few studies done with the feeding of larval shrimp,
I now only feed my larvae a cyclopoid species of copepods and only
resort to the use of brine shrimp when I am unable to collect copepods
due to the weather. In these studies, it was noted that when the larvae
are fed brine shrimp, the rate of larvae loss is extreme, upwards of 96
percent. This may explain my first poor attempts at keeping the larvae
alive long enough to settle out as I had assumed that baby brine shrimp
would be an adequate food source for the duration of the larvae
development. Harlequin larvae do not swallow food whole, they catch
food and chew on it, so food size is not very critical, although being
too small is no good as the larvae will most likely ignore small food
I have also noted that harlequin shrimp
larvae are relatively
large compared to other commonly kept shrimp species and are quite
capable of consuming copepods during their entire larval stage(s).
Having wild collected copepods also ensures me that their food source
is already naturally gut loaded. For those of you who must culture
their own live food, I would first master the art of breeding and
raising copepods in order to have a ready supply on hand. There are a
great many resources online to guide you in the set up and culture of
live foods. Of course, you can also buy your live food(s) directly and
avoid having to culture your own. This may become expensive though and
could also endanger your larvae if for what ever reasons, your
shipments are delayed or lost.
The one great advantage we have over
breeding other shrimp
species is that other such species, such as the peppermint shrimp, must
have their food source available within a matter of hours after
hatching. This means those who do raise such shrimp must be forever on
guard to collect the newly hatched larvae or risk losing them to
starvation. We, on the other hand, do not have to stay up all night
watching for the hatching event as the harlequin larvae can survive up
to five days without eating. I do not suggest that you wait that long
to move the larvae or provide them with food, but it at least allows us
to get a full nights sleep and can collect them at our leisure the
following morning after a hatching event.
If the adult shrimp are being kept in an
aquarium that has power
filtration or water pumps of any sort, then it would become important
to catch the newly hatched larvae right away so as to avoid them being
trapped in the aquarium's filtration. This is yet one more reason that
I keep my breeding pairs in small, dedicated tanks using nothing more
than an air stone, a layer of sand and a bare base rock or two.
Commercial dry foods are available and
have been used for other
shrimp species. This is something I have not tried and doubt that I
ever will. I do not have such foods available to me here and can not
test if such foods are a viable alternative for harlequin shrimp
larvae. If you do decide to try either the dry or frozen commercial
mixes, keep in mind that the food must remain suspended in the water.
If it drops to the bottom, the larvae will ignore it, just as they do
with live foods that are not moving. My biggest worry with
prepared foods would be in their polluting the water quickly.
One other point I would like to make
about feeding involves the
size of the aquarium used for the larval rearing tank. I personally
prefer a much smaller aquarium simply because it takes a lot less
copepods to create a large concentration of food for the larvae. This
is important as the larvae do hunt by sight and will chase and hunt
down copepods as they swim or drift by. Having a good concentration of
copepods ensures they have a chance of catching their food.
large tank, the chances of their food bumping into them is greatly
reduced and may effect the survival of the larvae. I would keep to an
aquarium no larger than five gallons. With that said, the smaller
aquarium will be a bit more demanding on you to ensure good water
quality, but I feel the extra maintenance is worth the trouble if it
means the larvae are being fed well.
If you have the choice of copepod
species, I have found that the
Cyclopoida (cyclops) species are best, simply because they remain free
swimming in the water column and do not crawl on the glass or
substrates as other species do. The larvae would have a hard time
trying to visually hunt them as well as being unable to grab them off
of the glass or unable to find them at the bottom of the kreisel. In my
opinion, the Harpacticoid species of copepods are unsuitable as a
harlequin larvae food source. If Cyclopoid species are unavailable to
you, the Calanoid genus may offer some alternatives. Acartia tonsa eggs
are now available through AlgaGen.com.
Please let me know if you are aware of any other sources of copepods
through my Contact Page. Thank you.
A Cyclopoid species of
Harpacticoid species of copepod
A Calanoid, Acartia
If you have access to a microscope or a quality magnifying glass, you
can remove one of the larvae every few days and watch the changes they
go through after each molt. I find it fascinating to see how after each
molt, they gain another body part or two. Do not be surprised if on
occasion you can not note any changes as shrimp larvae are known to
perform "mark time" molting which appears to be a slowing or delay
mechanism for reasons unknown. Such molting extends the length of time
the larvae remain in a specific stage of their development, which is
why it is impossible to say with certainty how long a given shrimp
species larval period will be. For the harlequin shrimp, the average is
between four to eight weeks.
If you do decide to examine your
larvae, ensure they do not
remain outside of their holding tank longer than a few minutes. They
are very sensitive to the changes in temperature and salinity that will
occur if left on a microscope slide or in a small shallow container.
Upon hatching, the harlequin shrimp larvae appear much more developed
than the other commonly kept shrimp species such as the peppermint
shrimp. They do not have to eat within their first few days, although I
like to start them out right away on baby brine shrimp and switch over
to copepods after one week.
DAY TWO : After their first molt, note how their
eyes are now more stalked. The mouth parts also appear more developed.
DAY FIVE Much more developed and are now very
aggressive little predators of copepods.
Thats it, this is as far as I have been able to come with
raising of the larvae. Again, I believe my troubles have been due to
water quality issues and hopefully I am now past that point. Having
allowed the kreisel to fully cycle for two months should give me a fair
chance at success. As with all things Marine, patience will be the
first art you must master. I will of course update this
if, and when I can progress further.
As you can see, this little endeavor is not for the faint hearted or
those not willing to put in the time each day. Myself, I would, and
hopefully soon, will take satisfaction in not only being
successful with breeding a marine species, but also in being able to
make the young adults available to the trade and thus take that little
bit of pressure off of the wild stocks here locally. Besides that, its
just plain fun! If you have any further questions, you can contact me
through my website and I will do my best to get you the answers to your
questions. Hopefully this article has covered enough ground to answer
the majority of them, or at the least, it got you off on the right
foot. I hope you enjoyed it!
I would like to thank my wife, Linda, for her continued support and
understanding while I pursue my many marine interests. A special thanks
also goes out to hobby experts, Syd Kraul of Pacific Planktonics, Eric
Borneman and Dr. Ron Shimek for their teachings and advice. I also
highly appreciate the editorial services that Carmalee Scarpitti
contributed. I can only imagine what a herculean effort it must have
been to correct my grammar and spelling, Thank you!
1. Kirkendoll, April, 2001. How to Raise and Train Your
2 Plankis, Brian. 2007. Hobbyists advancing the Hobby, part II : An
introduction to Project DIBS Reef keeping Magazine.
3. CCIF. 2001. Analysis of Destructive Reef Fishing
Practices in the Indo-Pacific. CCIF Marine Program.
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