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How to Care for a Violet Goby (Dragon Goby or Dragonfish)

I am the proud owner of a violet goby and I love giving tips on how to care for them.

The Violet Goby

The Violet Goby

Dragon Goby Care and Maintenance

A violet goby, or Gobioides broussonnetii, is sometimes called the dragon goby or erroneously called a dragonfish (the name of the arowana, among other fish). It prefers brackish water and is native to the swamp waters around Florida and the Gulf of Mexico.

The violet goby is a long, slender fish that resembles an eel (but is definitely not an eel!) and has a silvery-gold iridescence to its skin. They can reach lengths over two feet in the wild. The dragon goby has ventral fins that allow them to cling to the walls of the aquarium. Their dorsal fin runs almost the entire length of their bodies.

Are They Aggressive?

Dragonfish are carnivores and mistakenly labeled as aggressive fish. But, ironically, these fish are the ones that get bullied. They are not aggressive at all, preferring to hide in the sand, behind rocks, and under plants.

Their teeth are very sharp. But in the wild, they use them to scrape algae off the rocks in their environment. They don't use them to fight other fish. These fish are scavengers and typically scoop up large mouthfuls of the substrate and sift through it for edible material, spitting out the substrate and eating the food. They also have large gills that allow them to filter and expel sand.

Requirements for a Dragon Goby Aquarium

Tank RequirementsFood Requirements

50 gallons minimum

Live aquatic invertebrates

25 gallons per Dragon Goby fish

Freeze dried bloodworms

pH between 6.5 and 8.5

Algae wafers

Low ammonia levels

Flake food

Aquarium sand substrate

Lots of variety in their diet

Temperature between 77 and 82 degrees

Brine shrimp

Lots of hiding places

Shrimp pellets

Tank Size for the Dragon Goby

The violet goby needs lots of space. A good rule of thumb is 25 gallons for each specimen. It is recommended that you start with 50 gallons at the minimum. The tank should also be at least four feet in length.

These fish are territorial when it comes to living with other dragon gobies, so it's a good idea to have a six-foot aquarium for two of them and larger aquariums for multiple gobies.

How Big Do These Fish Get?

In the wild, these fish can grow up to 24 inches long; however, they rarely grow any larger than 15 inches when kept in an aquarium.

Rocks can cause injury to the Dragon Goby's delicate fins. This shot was taken before we added the sand to demonstrate how the fish lays on the rocks.

Rocks can cause injury to the Dragon Goby's delicate fins. This shot was taken before we added the sand to demonstrate how the fish lays on the rocks.

Substrate and Plants

The floor of their new home should be a sand substrate because they like to bury themselves in it. Rocks can cause injuries to their fins, leading to infection and possibly death.

They also need a lot of hiding places. Plants, logs, caves, and anything else they can back themselves into will provide much-needed shelter.

Plant Recommendations

Dragon gobies enjoy a variety of plants, including:

  • Anubias
  • Hairgrass
  • Marimo Balls
  • Vallisneria
  • Java Moss
  • Java Fern

When selecting plants, keep in mind that these fish can easily uproot plants that are not secured above the substrate level. Be sure to protect any plants from possible digging.

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Water Type and Temperature

Dragon gobies also need very clean brackish water. It is best to change 10 to 15 percent of the water every week and keep up on any maintenance your filter may require. You will also need a water heater and thermometer.

Dragonfish prefer temperatures between 77° and 82°F, the ideal temperature being 80°F. Our dragon goby seems to prefer 78°F, however. The pH should be kept between 6.5 and 8.5. Ammonia levels also need to be kept low; these fish have a high sensitivity to ammonia. It will cause the fish to scramble to the surface and gasp for air. If not diluted quickly, the ammonia will kill the dragonfish.

The teeth make them look mean, and their huge mouth makes them look grumpy.

The teeth make them look mean, and their huge mouth makes them look grumpy.

Feeding a Violet Goby

These are hearty fish and tend to be scavengers, sifting through the sand to find algae and other small organisms. In the aquarium setting, gobies will eat frozen black tubiflex and blood worms along with sinking shrimp pellets.

They have very small throats, so anything they eat must be very small. Algae wafers and flake food can also be on the menu. Our dragon goby dislikes flake food and much prefers algae wafers.

It should be noted that dragonfish may not eat for the first one to two days after you introduce them to their new home. After they have acclimated, they should be fed once a day and only fed as much food as they can consume within two minutes.

These fish are shy and nocturnal, preferring to be active at night, which can give the owner quite a scare. They do adapt to feeding during the day, however, and do so rather quickly.

When well cared for and kept in brackish waters, Dragonfish can live for over 10 years!

When well cared for and kept in brackish waters, Dragonfish can live for over 10 years!

Keeping Dragon Gobies With Other Fish

Violet gobies should not be in a tank with aggressive fish such as oscars and tiger barbs. Oftentimes, the dragon goby will become the victim of fish bullying, so it is best to keep them with smaller, non-aggressive fish. However, very small fish may become dinner for the dragon goby.

Medium-sized fish that are tolerant to brackish water make the best companions:

  • Mollies
  • Knight Gobies
  • Guppies
  • Swordtails
  • Orange Chromides
  • Platies
  • Bumblebee Goby
  • GlassFish
  • Celebes Rainbowfish

It is important to note that these fish have very small eyes, and are almost blind. This makes it difficult for them to compete with other fish for food. They find their meals using their sense of smell rather than sight.

Adding fish to help keep the tank clean will keep your Violet Goby healthy and minimize some of the cleaning you'll need to do. The best choices for this are amano shrimp, nerite snails, and ghost shrimp.

Illness Susceptibility

Dragonfish are hardy animals, but like everything else, they can be susceptible to some illnesses. They are most commonly affected by bacterial infections such as fin rot or Columnaris.

Fin Rot

Fin rot causes a fraying of the fin edges which also turn black. The disease progresses until it reaches the base of the fin and is a result of a bacterial or fungal infection.

The bacteria Pseudomonas fluorescens causes the fins to rot in a ragged fashion. It can also be caused by a fungal infection which typically causes the fins to rot in a more even way. The fungal version also causes a white edge on the fin. Both fungal and bacterial fin rot can affect the fish at the same time.

The fungal version also causes a white edge on the fin. Both fungal and bacterial fin rot can affect the fish at the same time.

Fin rot is typically caused by:

  • Poor Water Conditions
  • Stress
  • Injury
  • Poor Diet

It can also be a secondary infection in a fish that is already suffering from a primary disease that is causing stress.


Columnaris (also known as cottonmouth) is caused by Flavobacterium columnare which is a rod-shaped bacterium that is gram-negative and aerobic. It is much more virulent than fin rot but can mimic it in the initial stages causing a ragged fraying of the fins.

The skin of the fish will begin to appear ulcerated within 24 to 48 hours which is followed by loss of the epidermal layer and then eventually cloudy or white-colored patches that resemble the appearance of fungus.

These patches typically manifest in the filaments of the gills along with mucous which can also appear on the dorsal regions and head. The gills may begin to necrose, changing color to a light or dark brown and then black (the final stage of necrosis).

The most common symptoms of Columnaris include:

  • Rapid and Labored Breathing (caused by damage to the gills)
  • Lethargy
  • Twitching
  • Rubbing the body against objects
  • Inflammation around the infected areas
  • Redness
  • Anorexia
  • Death (typically within 48 to 72 hours unless treated)

Both fin rot and Columnaris are treatable, although fin rot has a better prognosis. Both diseases can be treated with antibiotics (or an anti-fungal in the case of fungal fin rot) and the temperature of the tank should be lowered to about 75°F to minimize virulence.

Buying Your Dragonfish

If you purchase your dragon gobi from a reputable pet shop, they should already be kept in brackish water. Make sure to ask what type of water they are being kept in so that you can prepare your tank before bringing the fish home.

Fish kept in stores like Walmart or large chain pet stores are typically kept in fresh water because it's easier to maintain. These fish can do well in fresh water, and it is possible to transfer them from brackish to fresh with a bit of transition. However, these fish tend to be much healthier in their native, brackish water.

A Word of Caution: Escaping Fish

These fish are excellent escape artists. If the water quality is not to their liking, they will float on the top of the water, gulp for air, and attempt to leap out of their tank.

I woke up to find my dragonfish nowhere to be found. My daughter said she heard a noise and saw him fall behind the dresser, and sure enough, that’s where I found him. He was about two feet away from his tank! For a small fish, that's a long jump.

I’m not sure how long he was there, but he was actually still alive. We have since changed the hood on his tank, and he has earned the name “Fumbles."

A Personal Note

Unfortunately, when we bought our violet goby, we weren't told any of the above information. The pictures you see in this article were taken as we were setting up the tank and before its completion. Our fish was quite active during this time so it was easy to get pictures. But as you can see, we started with rocks instead of sand, and didn't have a lot of places for him to hide.

If you decide that this fish is right for you, don't buy it from Walmart like we did, and if you do, make sure you research this beautiful creature as much as possible before you bring it home. They really are beautiful, but they do require maintenance and a very specific environment. They are also very hearty fish, and they tolerate change well if it's done slowly.

The beautiful length of a violet goby.

The beautiful length of a violet goby.

Additional Resources

© 2013 Mel Flagg COA OSC


Valentino on December 22, 2019:

What do dragon fish eat

Megan on August 12, 2018:

My brother and i had a two dragon gobi when we were kids. We kept them in this tiny fish bowl and id find my brothers gobi out of the bowl every morning. Im looking to get a two more and im thankfull for the research you did.

Bianca Golman on March 19, 2017:

Hello, so I have 1 or maybe a few questions, ok so I have a 50 gallon neon tetra fish tank, I went to PetCo 3 weeks ago and bought 2 cherry barbs, 3 black skirt tetras, and 1 silver molly, I’m not much of an expert about fish, but would any of those fish go good with the dragon fish? another question? LOL, umm I have 3 cats that won’t go near my fish tank, if the fish perhaps does see one of the cats looking at it, will it be afraid or what? also where do I find the live aquatic invertebrates at? I am going to petco sometime next week.

Aaron on February 01, 2017:

Probably too much amonia, dI a good water change and maybe an air stone... also you'll probably need a 125 for that many goby, they can reach 24"

Jennifer Clark on January 31, 2017:

I have 5 that were a gift and am kinda clueless. Have yours ever stood straight up in the tank and gulpped air? Mine do it all the time also hug the heater alot even tho the tank stays around 75 degrees. any help i can get would be awesome.

Amber on December 13, 2016:

I want one for Christmas and I want to get it from Walmart what should I do? I think I should just get one but should I ?

Mel Flagg COA OSC (author) from Rural Central Florida on October 24, 2016:

When we bought our Dragonfish, we were told brackish water. But I have heard many people say their fish does well in freshwater. If you currently have the fish in brackish water, I would not change him to freshwater, it will be too much of a shock to his system and will probably kill him.

Brittany Preedom on August 19, 2016:

I've had mine now for seven years. Tried to acclimate her to brackish water and she freaked out so we just kept her in our 56 gallon freshwater. She's now well over 14 inches and is a doll. We have kept her with guppies, mollies, platys, sword tails, and all other kinds of fish. She has outlived them all. We named her Tiamat. Like you we bought her from Walmart but ours was nothing but skin and bones. She's very healthy and active and never hides. Also she has never once escaped. I also own a snowflake eel in another tank and she has never escaped either.

Elisa camacho on July 10, 2016:

I bought a goby and was all excited I woke up the next morning and it was gone no where to be found

dan on February 29, 2016:

will my dragon fish survive in freshwater?

Destiny on February 17, 2016:

I have one of these fish and has had it for 5 months and I come home and the fish is laying upside down but still breathing. Do you know what could be wrong? I had a gas leak in the gas could it have killed it?

Linda raley on November 21, 2015:

We just baught one of these creepy critters for my hubby and it escaped and is no where to be found. He is very upset right now.

Mel Flagg COA OSC (author) from Rural Central Florida on April 09, 2015:

@KristenHowe Thanks!! They are beautiful fish, but can be tempermental lol

Kristen Howe from Northeast Ohio on April 09, 2015:

Great hub about a caring for a beautiful hub. Nice tips on how to buy one and take care for it. Voted up for useful!

Mel Flagg COA OSC (author) from Rural Central Florida on June 02, 2013:

@Faith Reaper, I had no idea what a Dragon Goby was when we bought him. I just knew he looked REALLY cool. They really are beautiful fish. They can be quite graceful when they swim, but they don't swim all that often. They mostly hide. Although Fumbles seems to have gotten used to us, and is will eat in front of us lol

Faith Reaper from southern USA on June 02, 2013:

Very interesting and I am one who has never heard of such a fish.

I do love to watch fish swimming around and the calm feeling it promotes.

Blessings, Faith Reaper

Mel Flagg COA OSC (author) from Rural Central Florida on May 31, 2013:

Thanks Billybuc. I agree watching my fish tank is so very relaxing. Almost meditative really. And actually it's our daughter's tank lol, we got it as her birthday gift this year. It was surprisingly cheap to set up, but they can be expensive to maintain.

Bill Holland from Olympia, WA on May 31, 2013:

I wish I had the money to have a fish tank. I could totally get into it as I find it a very peaceful hobby. Great information here my friend.

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