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This page lists my experiences with Violet Goby (also known as Dragon Fish, Dragon Goby). While some of the fish-related Web sites you may find may give you the scientific information, very few of them probably tell you the information in this post. I should point out however that these are my personal experiences, your mileage may vary, although the information here is probably a lot more accurate than anything your local fish store might tell you.

Firstly, here are some scientific facts and figures:
Scientific name: Gobioides broussonnetii
Name: Violet Goby
Size: Up to 2ft long
pH range: 6.5 – 8.5
Temp: 24–26°C / 76–78°F
Salinity: 1.005-1.008

As the article I linked above told you, I was sold this fish as a freshwater, semi-aggressive fish by Petland in Bolingbrook, Illinois. I specifically asked for something which could share a tank with aggressive Tiger Barbs and which could be a ‘centerpiece’ large fish for my largest tank. It was not long before I found out the ‘Dragon Fish’, as they named it at the store, requires Brackish water (with a little ocean salt) as they come from where ocean meets river mouths. It also wasn’t long before I saw my Tiger Barbs picking on this fish mercilessly, with me eventually discovering that not only is this fish not aggressive in the slightest, it’s also completely blind and couldn’t defend itself even if it wanted to. So after setting up a new tank for this fish, who was probably six inches long at the time, adding salt to raise the salinity and transferring bacteria over in both the substrate and filter media I saw him seeming much happier as he hid underneath a decoration in his new home.

I feel I should point out why I say two feet as maximum size. Every Web site seems to say 1ft, but then I saw these photos:

About 3½ years old.

About 3½ years old.

4 years old. Massive fish apparently over two feet long.

4 years old. Massive fish apparently over two feet long.

The photos above came from this page and were submitted by a fishkeeper who wanted to point out her fish was over the “1 foot maximum” listed on the page.

My fish has been in two different tanks and has shown quite a bit of varying behavior. He has shared his tanks with a few different fish and shrimp. There’s been some interesting observations I’ve made which hopefully can assist you as you welcome your Violet Goby into an aquarium.

Dragon Fish/Violet Goby - Intimidating, but harmless.

My Dragon Fish/Violet Goby - Intimidating, but harmless.

Water Salinity

Probably, along with tank size and feeding, this is the most important thing to get right with this fish. Although often kept in freshwater in stores and although they can survive in it for quite some time, it doesn’t do their immune system any favors and I actually noticed a lump on my Violet Goby when I let the salinity drop over a few weeks (I never measured too much for accuracy because these fish come from an area where salinity fluctuates), but it does seem that with a sustained lower salinity he became sick. I made no treatment whatsoever except another water change where I restored the salinity to 1.005 and after a matter of days the lump on his lip disappeared. Ever since this happened I have been very careful to keep the salinity fluctuating between 1.005 and 1.008 only and have never seen any signs of problems.

Tank Size

When I bought this fish he was supposed to go into a 55 gallon freshwater tank. Learning he required Brackish I decided to purchase a 29 gallon and it is in that tank that I noticed different behavior than I now see in his current home (55 gallon brackish).

In the 29 gallon I had two large Texas Holey Rock pieces (Limestone, so they help keep the pH high). The fish would spend all his time hiding, so much so that he would often miss meals. I am almost certain that this fish navigates based upon water movement as when my hand was in the tank he would often react to it even when it wasn’t possible for him to see it. So I think such a small tank left this fish feeling ‘attacked’ on all sides.

In the 55 gallon brackish tank (with the same rock type) I noticed him immediately exploring more than he ever had in the 29 gallon. I arranged the rock along the bottom of the tank in a way that allowed him to either have or be near cover at all times and the difference is astonishing. He comes out at feeding time and competes with the other fish for food which becomes trapped at the edges of the rock on the substrate.

I would really like to say that it’s more than the larger tank which made the difference (partly because I don’t want to feel guilty for having kept him in a 29 gallon), but I think that’s wrong. I think it’s totally down to the size of the tank that has allowed this fish to become more confident.


Feeding a Violet Goby who lacks the confidence to come out of hiding is very difficult. These fish are scavengers and I often had to fully melt frozen food and drop it right infront of him for him to get any. He so seldom came out of hiding that he would miss meals entirely. In the 29 gallon tank I arranged the rocks so that with the direction of water flow food would become trapped inside his hiding place. This worked well and so did sticking my hand into the tank and actually placing the frozen food underneath the rock with my hand. It would eventually melt and dropped food ontop of him.

After moving the fish to my 55 gallon brackish, however, I haven’t had any issues with feeding. He must feel safe enough due to the combination of rock placement and tank size to come out and seek food whenever he smells it. Try to arrange things so that food becomes trapped at the level of the substrate as I’ve never seen my fish come to the surface in search of food.

For the record, this fish never ate anything living that I saw or noticed missing. He shared a tank with Ghost Shrimp, Platies, Guppies and Fry (babies) Guppies and Platies. If he did manage to eat Fry, it was purely out of dumb luck. This is not a hunter, it is a scavenger. I have seen him eating flakes, brine shrimp and bloodworms, all from the surface of the substrate.

Tank Mates

Never, ever, ever put this fish with any aggressive fish. These fish are harmless and cannot defend themselves from attack. All freshwater fish are out because this is also not a freshwater fish. There’s no way you can justify to me why, based on my experience, you have one of these fish with either of those groups.

So here is a list of fish I have successfully kept with my Violet Goby:

Bumblebee Goby – These tiny little brackish fish are lots of fun to watch and although definitely mouth-sized are under no threat from the Violet Goby. Again, an accidental meal is always possible with something this small, but I doubt it.

Platies and Guppies – As these fish can be acclimated to Brackish water they make a very nice tank mate for the Violet Goby. The Fry could accidentally be sucked into the Gobies mouth I suppose, but I doubt it.

Freshwater Flounder – This isn’t really freshwater, it’s brackish. This substrate-dwelling flat fish can overpower small fish but is no threat to the Goby. The Goby is definitely no threat to the Flounder.

Ghost Shrimp – No danger either way. The Ghost Shrimp can leap backwards too quickly for the Goby to even accidentally eat them. Ghost shrimp are at home in fresh and brackish water.

Knight Goby – Excellent brackish tank mates. They give the Violet Goby plenty of space but are usually territorial with other Knight Gobies.

Green/Silver Scats – Very large brackish fish that are relatively harmless. They will occasionally eat Ghost Shrimp, but everything else on the list above should be safe. They are no threat to the Violet Goby.

Ramshorn Snails – These snails can survive low salinity of 1.005. I have seen the Violet Goby suck in small snails and eat them while sweeping the sand, but I am certain it was accidental.

Malaysian Trumpet Snails – These snails can survive low salinities. I have never seen even an accidental meal being made of these snails.

I’ll say it once more: If you are adding something not in the list above, then do your research. If they are not Brackish or they are aggressive towards other species you should NOT keep them in a tank with a Violet Goby. It really is that simple.

Conclusions on the fish

A wonderful “oddball” fish that is very interesting to look at. The only real problem is that you don’t see them very often as they’ll only come out when they smell food (or if they are not confident, they’ll only come out when extremely hungry). Mine has a fantastic silver coloring with blue along the top and a purple hue around the body and head area especially.

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Left: Rotkeil 'Severum'.

My first word was "fish", and my earliest memory is of the fish tank my parents had while I was a baby. Starting with a 10 U.S. gallon tank and easy fish like Zebra Danios, and some Cory Catfish, I quickly upgraded to 55 then 125 gallon tanks, and at one time had seven tanks in a relatively small apartment.

I've had some interesting experiences with my fish, such as moving them 1000 miles across the country and of course going through that lesson everyone needs to learn; not to trust the fish store. I've ordered fish online, but now primarily use a store called Animal Island in Midlothian, Illinois. This store accepts fish returns for partial store credit, so I have used this to my advantage and kept many different types of fish, gaining experience in a short time about a huge number of species.

My favorite fish so far is the Vulture Catfish, which is an absolutely beautiful long-whiskered and active catfish. My current biggest fish is a Fahaka Puffer.


Tim is British and lives in the United States with his wife and kids.

He works for software developers Image Space Inc. and Studio 397 on their racing simulations, and is a fan of Gaming, Motorsports, and photography.

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