a Dragon in my Tank!
by "Pufferpunk" ( aka Jeni C. Tyrell)
There are a few creatures that are claimed to be “so ugly, they’re cute” or “so
ugly, only it’s mother could love it”. This dragon is not quite the same.
The Dragon Goby is a gentle monster--it's nowhere close to as mean and evil as
it looks. Though it looks like a vicious predator, it's really the opposite.
You cannot help but notice its weird appearance--unlike any fish I know.
Its tiny eyes, huge mouth and long dragon-like dorsal fin set it apart from all
other fishes. A lot of folks would call this fish ugly but I find it very
lovely. It is the largest goby in the Caribbean and the only one with this
distinctive eel-like shape. Yes, it looks like an eel with tiny, beady
eyes that rest near the top of it’s big head and a large mouth, lined with sharp
teeth. This fish also has a beautiful bluish/pink metallic sheen to it, and a
long, undulating dorsal fin, closely resembling the serrated back on mythical
dragons (hence the “Dragon” name). I’ve always compared it to the monster
that pops out of that poor fella’s chest, then slithers away, in the movie,
Alien. Now that one is ugly!
With it's long serrated dorsal fin, it
is easy to see where the common name "Dragon Goby" comes from.
Meet The Dragon Goby:
Known as The Dragon Eel or Violet Goby)
Distribution: Western Atlantic: from Charleston, South Carolina southward to
Florida, along the Gulf of Mexico coasts of Alabama, Mississippi, Louisiana, and
eastern-central Texas; along the Caribbean coast of Colombia, eastward to
Venezuela, Surinam, Guyana, French Guiana, and Brazil as far south as Rio Grande
do Sul, Brazil.
A face only a mother.... or aquarist
could love! Photo by Scott Grahm
Size: Generally they grow to around 15”-18” but fish as large as 2’ have
been found, if kept in a large enough tank.
Water Conditions: Brackish water conditions. Specific gravity around
They will eat bloodworms, Cyclops,
worms, brine shrimps, Daphnia, chopped worms, fish and shrimp, and any
other similar food. They will also eat algae wafers, algae and small sinking
pellets of fish food.
Recommended Temperature: 73 to 77F, 23 to 25C, a little cooler than most
Although they are not particular about pH,
these fish must be kept in brackish water! You must use marine
salt and measure it with a hydrometer or refractometer.
Its normal habitat is mud-bottomed areas in river mouths, estuaries, salt
marshes and even the ocean down to 100ft deep. They may enter fresh water
occasionally but are healthiest in brackish water and that is how they should be
maintained if they are to thrive. Keeping it in freshwater will compromise
its immune system, causing disease and early death. The first one I had
was kept in fresh water (before I knew better). It did live to 5 years.
At around 2 years, it started to develop pink tumors all over its body. By
5, it had developed one inside its mouth, until it could not close its mouth
anymore. Since they are filter feeders, they must be able to close their
mouth after gulping in food and water.
Not to be Confused
These marine gobies are often referred
to as "Dragon Gobies".
Amblygobius semicinctus on the left and
Amblygobius sphynx, right. Photos by Robert Fenner
They are mainly scavengers who put forth only minor effort in searching for
food. Their primary method of obtaining food is by scooping up mouthfuls
of sand and sorting the edible things from the substrate, then they spit out the
substrate and swallow the food particles. They also use their lateral “chin
fin”, to dig around the substrate. It feeds on diatoms (the brown
algae so common in aquariums), various sea algae, small shrimp and anything else
that can fit in its mouth, EXCEPT fish. They thrive on Wardley Shrimp Pellets.
Mine has been known to suck on an algae wafer until it gets soft and then gulp
it down. Dragons have tiny eyes and extremely poor vision.
They generally hide all day and come out at night to feed. Since it can’t
see or swim very well, the number one cause of death of these fish is
starvation. Do not keep with more aggressive eaters, as it often has
difficulty finding food before the other fish in their aquarium have eaten all
of the food. It is best to drop their food near the opening of their
cave, after lights out. Since they have
been observed in the wild to eat continuously, it would be best to meter out
several small feedings throughout the day. Do not overfeed and clean up any
uneaten food. Lacking the normal fish’s swim bladder, they are poor
swimmers and wiggle back and forth like a snake in the water or scoot along the
substrate and rocks on their lateral fin. Sometimes you can see them
standing vertically on their pectoral fin, sticking to the glass by their
A sandy substrate is best for them to dig around in. Sharp rocks can
injure the fish. They will create a burrow under or behind a large rock.
Being quite shy, dragon gobies like to hide in caves but the caves need to be
small because they seem to prefer tight fitting places. PVC pipe will do well
also. A large open cave in full view will simply cause the goby to burrow next
to the farthest side. You can trick them by leaning a flat rock against
the front glass. They’ll move into their new cave and stay right out front.
They will chase out other fish that try to barge in on their territory.
With a heavily decorated tank, they will feel secure enough to come out more
often during the daytime. Live plants do not do well in brackish water.
You could try java fern or java moss but plastic or silk plants are recommended.
Most aquarium shops and even many books have stated that these fish are fierce
predators. Despite its aggressive reputation it is a very peaceful fish and
won't harm smaller fish. They have been known to squabble amongst
themselves but it is ok to keep them with conspecifics, as long as there is
enough room. Dragon fish are best kept singly, unless a large group can be kept
in a tank of about 100 gallons or more. In small tanks or small groups, one
larger Dragon Goby will dominate the others and some may be bullied or not get
enough food. You can keep them with other brackish water gobies, like
Bumblebee Gobies or Knight Gobies. It cannot compete with aggressive or
Since these are scaleless fish, Dragons are more prone to skin diseases.
They are also more sensitive to medications, so the best preventative to disease
is a clean tank. Good filtration and weekly water changes will help keep
their water conditions pristine. They must be introduced into a fully
cycled tank. If purchased in freshwater, cycle the tank as freshwater and slowly
bring the goby’s specific gravity up .002/week, until you have reached your
Sexual dimorphism of G. broussoneti is distinguished by a small
urogenital papilla, which is in the ventral region between the anal opening and
the anal fin. In the females it is short, blunt and has a yellow coloration; in
males it is thin, pointed and has a smooth appearance.
Spawning is possible in a large aquarium.
Harper, in Tropical Fish Hobbyist (#473), documents success in captive
spawning on pages 130-132. He suggests using a spawning group of one male and
three or more females. The tank should be furnished with hiding places for the
females and as a nest for the male. The fish should not be fed for a week and
then conditioned on live foods. The salinity should be lowered and then raised.
The male will spawn with several females over the course of a day. Following
spawning, the females should be removed and the male will guard the eggs. After
36-48 hours, the fry hatch and the male should be removed. After the egg sacs
are consumed, the fry can be fed roftiers and green water containing algae.
After a month, Artemia nauplii can be fed. (For more information, please
check the article in TFH). There are no other spawnings in captivity that has
Questions about reproductive seasonality, ovarian development and spawning of
need further investigation.
Note the sandy substrate and plenty of
cover. Photo by Scott Grahm
This is not a fish for beginner aquarists or even experienced freshwater
aquarists beginning in brackish water. A
lot of these are sold because of their odd appearance and common names. Who
wouldn't want a purple dragon? But that is insufficient reason to buy a fish and
a lot of these animals are kept inadequately, as is the case with most brackish
species. Too many aquarium shops tell folks to just “add a little aquarium
salt” to make your tank brackish. You need to be dedicated to keep this goby,
making sure to keep their water very clean and that they are eating well.
If kept properly, this exotic, unusual fish can live close to its teens. All in
all, this is a fascinating, beautiful oddball, for an advanced aquarist to keep
in his or her brackish tank.
P.S. You can visit Jen's website at: