for a Mandarin Goby
(in a Nano Tank)
not beat around the bush. The purpose of this article is to discuss
housing a mandarin goby in a nano reef tank, i.e. a 5-20 gallon saltwater
aquarium. And you probably thought I couldn't get any more controversial...
to the heat on this topic, please forgive the following disclaimer.
However, if you've ever had a passing interest in mandarins and possibly
keeping one in a nano tank, you've no doubt seen the blatant hostility
from all the nay-sayers out there. I've done a lot of reading about
mandarin dragonets, and I've come to the conclusion it is possible to
house them in a nano tank as long as they are given the right conditions.
I believe keeping a healthy, happy green mandarin goby in a ten gallon
tank is possible. I also believe we will soon be seeing tank-raised
and aquacultured green mandarins in the next ten years. Feeding issues
will be a thing of the past, and farm-raised mandarins will eagerly
accept frozen and processed foods. Nano tanks are very new to the saltwater
scene, and fifteen years ago a marine aquarium under 55 gallons was
absolutely unheard of. Thanks to new lighting technology and the Berlin
method of natural filtration through live rock, smaller quantities of
water are holding fish and corals aquarists never dreamed of keeping
in 100+ gallon tanks.
Mandarins are some
of the most popular, easily available, and cheapest fish on the saltwater
market. They experience the greatest mortality rate of marine fish as
well. Given these two facts, and given the nature of capitalism (let
alone the evolutionary advancement of the marine and reef hobby), I
believe we'll be hearing a lot more stories of mandarins eating frozen
and pellet food and thriving in tanks once thought impossible to sustain
In fact, this is
already happening. Many marine hobbyists who've done their homework
have reported success in keeping mandarins in nanos, and several have
even weaned them onto pellet food. Unfortunately, people are often afraid
to admit their success on forums. As mentioned above, keeping mandarins
in anything but the traditionally accepted housing--100 gallons, 100+
pounds of live rock, a 2-year old, "mature" tank--brings out
the worst in some people. For whatever reason, they will not open their
minds to even the idea of success.
I agreed with them. However, once I really delved into google and nano
fish forums, I found many different people reporting the same success
stories... a green mandarin eating bloodworms, a freshwater food (which
I feed my discus); a green mandarin being supplied pods daily from a
separate pod culture tank; a whole tank of mandarins eating Formula
1 pellets. They were always met with the same hostile or rude responses
and arguments. Your fish will starve after 6 months. They
cannot be kept in systems without an excessive colony of pods. Etc.
I am determined
to try and keep a successful and healthy mandarin in my ten gallon.
I have done my homework, and I hope you have too. Here are some more
- I will do everything
in my power to provide the mandarin with the nutrition and care it
- I believe experimenting
with pets is good, as long as the caregiver has done his homework.
- Fish are not
people. Attaching human elements onto fish or any lower animal is
a fallacy. I am not "torturing" a fish for selfish or aesthetic
reasons; I am advancing the hobby by trying to do what others have
successfully done before.
- If my experiment
fails, I am prepared to "eat" the fish and all the expenses.
I will return the mandarin to the LFS, and I will probably try again
with another specimen. If I fail again, I will most likely give up;
however, I will never condemn someone who tries the same thing.
- I will not know
if things are going swimmingly until I reach the six month mark.
The green mandarin, or Pterosynchiropus splendidus, is a member
of the dragonet family. They are also known as psychedelic fish. Rarer
specimens come in reds and there's even a spotted variety, but the
average mandarin you'll see in fish stores is the green mandarin male.
Males are selected over females because of their more impressive dorsal
hail from the Philippines and the Melanesian islands. They are naturally
found in reefs or coral rubble with rich sand beds, constantly on the
hunt for small crustaceans.
Each specimen is
wild caught and exported. Despite their popularity, they are not yet
endangered--as shown by their rock bottom prices. Though a mated, healthy
pair breeds and lays eggs often, cultivating the eggs and raising the
fry has not yet been done successfully on the commercial market.
In the wild, mandarins
can consume a vast number of copepods, amphipods, and other "pods"
daily. They are extremely difficult to wean onto frozen or processed
foods, and many mandarins will never accept anything but live pods.
This is why they are considered expert level fish and are thought
to best thrive in large, mature systems with copious live rock.
Though your odds
of success go up if you introduce the fish into a large, established
reef system, many still experience losses. The variety and stacking
of live rock seems to be as critical as the amount. The level of nutrients
in your tank is also important. Pods must be able to thrive if your
mandarin is to thrive.
have metabolisms similar to humming birds, they are always consuming,
but they only eat in small portions. Ergo, an inadequate tank can
have its entire pod population decimated in a matter of days. Good
conditions for your pod population to sustain itself is the number
1 way to successfully keep the mandarin goby.
I will arrange my tank to accommodate copepods, the mandarin's main
food source. Instead of a fuge or a sump I will culture the pods in
a separate venue: several quart mason jars on the windowsill. I will
inject the tank with fresh pods on a regular basis so the population
will always stay at adequate levels.
The image to your
left is a bottle of aquacultured copepods. Each bottle contains 1000
copepods of three different species. They are nutritionally dense and
provide the essential fatty acids that brine and other food often given
to mandarins do not. Also, if you're able to sustain a constant population,
you'll not have to worry about getting your mandarin to eat frozen or
processed foods ever again!
According to Dr.
Adelaide Rhodes, the creator of Oceanpods, "It is difficult to
believe that something so small could have such a significant impact
on the nutritional value of fish, but a good analogy is the dependence
of whales on krill. Krill are just another type of marine crustacean
rich in essential fatty acids, and the preferred food of many species
of whale, which filter the krill out of the water by pushing them through
the fine mesh of baleen found inside their mouths. Without the krill,
the whales would die. Think of the size of the whale compared to the
krill and you can begin to see how significant Copepods can be in the
marine food web." (Source
Please see Dr. Rhodes's
site for more
information about Oceanpods and how to begin your own culture.
My pod factory will
consist of multiple quart jars, each containing a nontoxic plastic dish
scrubber (the coarse type of sponge that looks like fishing net). Once
the progenitor batch of pods multiply and the population takes off,
I will split the culture to the second jar, and then the third, etc.
I estimate in a month's time I will be able to lift a scrubber from
one jar and shake out enough pods in various life stages to keep my
main tank's population at sustainable levels. The decimated quart jar
will then have enough time to rebuild its population while I pillage
the remaining jars once or twice a week or as needed.
In addition to
the copious pod population, I will attempt to wean the mandarin onto
frozen mysis, and ultimately, Formula 1 or Marine Cuisine. I've read
reports of an LFS worker in Australia having an 80% success rate with
getting mandarins to accept prepared or frozen foods. He used freshly
hatched brine shrimp and "gut loaded" them with bloodworms
and other frozen and processed fare, and slowly he weaned the mandarins
onto the regular foods.
Many hobbyists over the years have discovered a few tricks to help get
a mandarin eating or plump. I've outlined several of them below.
- Use a refugium.
- Create a "pod
pile" of small chunks of live rock in a corner. Pile the rubble
up so fish cannot enter and spray the area with minute bits of food
to herd the pods into the safety area to feed and reproduce.
- Target feed blood
or blackworms, mysis, or Marine Cuisine to a crevice in the live rock.
It is believed fish have selective memories and return to a location
that is known to hold food.
- Try feeding roe,
or fish eggs. These can be obtained at Asian markets under the name
of flying fish eggs. They look like the orange little balls on sushi
- Employ a mandarin
diner. Though this looks good on paper, I'll be very interested
to see if it does anything for a mandarin that doesn't eat prepared
- Stock your tank
with porous and gnarly live rock. More surface area the better, and
place them so there are fish-free areas. By many reports, mandarin
success has as much to do with the placement and type of live rock
as it does with the volume.
- Employ non-combative
tankmates that won't go after pods. According to several hobbyists,
some mandarins have duplicated the behaviors of other fish. One was
even reported to have imitated a crab and begun to consume baby brine
shrimp in the water column.
- Style your tank
around the needs of pods and mandarins.
I don't know if this will work. But I'm willing to risk a lot--the
fish, as well as a fair chunk of money--because I believe there is
no reason why this hypothesis will not hold water. Nothing tried,
nothing gained, as I see it. I've put a lot of thought and time into
this project, not to mention investment. I would love to see mandarinfish
in smaller tanks because they so easily get lost in the huge systems.
I've thought my way through every step of the way, and if I fail...
well, I can't say that I haven't been warned.
I've had the mandarin for one week now. As posted in my blog,
he continues to graze on the live rock, sand, and glass, and he continues
to snare a goody every 5-10 minutes. I've injected pods twice now
into the main tank. I added a scrubber pad into my little HOB filter
box. The idea of the scrubber in the filter is to spray the fresh
pods into the filter box and let them trickle down into the main tank
as they are attracted to light. Algae and detritus from the filter,
in theory, should sustain a small fuge-like population in the box.
Now the bad news.
The mandarin is
not as plump as I'd like him be. He has improved since purchase, but
I can still make out the line in his abdomen. I fear I may have bought
one too far gone. As I see amphipods on almost every patch of sand
and rock I look closely on, and I can find copepods with a flashlight
at night, losing him will not be for want of food.
I've been in touch
with Dr. Rhodes and I have started my second culture jar. However,
my first jar may have been contaminated. I introduced some algae into
the jar, and it could have possibly fouled the water and stunted the
culture. Today I removed most of the algae with a prong. I believe
most of the pods are deep in the sponge and out of my view, so I will
have to wait longer to see a population boom.
Do not add algae. It can hold unconducive hitchhikers as well as pollute
the culture. Also, wait until you are seeing large growth before adding
the scrubber. The pods seem to disappear into the pad and it is hard
to gauge when you're ready to split the culture.
Moved the scrubber pad from the filter box to the pod pile to prevent
a nitrate build-up. The pod pile is much larger and now offers much
more protection for the pods. At night I see amphipods everywhere. I
also added a large seashell with more scrubbing material wadded inside.
The mandarin is
looking better, I'm happy to report.
Pod production in
the jars is coming along nicely. I see thousand of tiny pods on the
second culture jar, the one without the pad.
I apologize for the lack of updates. My wife and I were gone for two
weeks on our honeymoon and my brother was house and fish sitting.
The mandarin is
still alive and more active than ever. I expected the pod population
to be decimated when I got back, but on the contrary, it continues
to boom. There are more than ever and they appear to keep multiplying.
There is now a new species of pods, little black ones smaller than
the clear amphipods and full grown copepods. They infest parts of
the glass that has slimy green algae as well as the sand and many
rock and shell surfaces.
I injected a new
source of pods a few days ago. Unfortunately, they are so small it's
very hard to tell if I'm injecting anything at all. I started a new
culture jar with the decimated scrubber pad I used to "replenish"
the main tank.
Here's some conjecture.
Perhaps the cultures are not entirely necessary. I believe the scrubber
pads and live rock rubble are the sole reason the population is not
only keeping up with the mandarin but growing larger. However, I cannot
safely conclude this because there hasn't been enough time to truly
appearance remains skinny. I find this disturbing because the frequency
of which he consumes pods has increased; he eats something every 2
or 3 minutes now. I don't know what this means, but I have some guesses.
One, he may have been too far starved when I bought him. Two, his
belly will come back slowly. Or three, he just appears this thin and
it's nothing to worry about. After all, the only information I'm going
on about their appearance has come from the same people who said this
experiment could never be done.
For more recent
updates, please see my mandarin fish