For years, dragon fish gobies have remained on the oddball fringes of the aquarium world. Their occasionally bright colors and intriguing appearance makes them understandably alluring, but it must be understood that ‘dragon gobies’ are not typical or easy pet fish to care for!
As a largely nocturnal species that requires special water conditions, I would only recommend dragon fish gobies for the most experienced fish keepers looking to create a specialist brackish tank setup.
It’s my sincere wish that this guide will serve as a useful introduction to keeping dragon gobies, but please see my recommendation at the end for further reading before you buy one.
Species Overview
| Dragon Fish Goby Info | |
|---|---|
| Scientific Name: | Gobioides broussonnetii |
| Common Names: | Dragon Goby, Dragon Eel, Dragon Fish, Dragon Fish Goby, Violet Goby |
| Care level: | Difficult |
| Life Span: | More than 10 years |
| Size: | 12 - 15 inches in an aquarium, larger in the wild |
Dragon Fish Goby Origin and Background
Hailing from the brackish waters of the Western Atlantic coast, dragon fish gobies are found wild in estuaries, salt marshes, and salty streams from Brazil to South Carolina.
Becoming more popular in recent years, these unusual fish go under various names in the aquarium hobby, including ‘violet goby’, ‘dragon fish’, ‘dragon goby’, and ‘Peruvian goby’
Because they’re not typical aquarium fish, dragon fish gobies require special care to remain happy and healthy.
Dragon Fish Goby Sexual Dimorphism
Some aquarists have found that male and female dragon fish gobies are difficult to tell apart – it seems there’s only one reliable means to sex them:
Whereas mature males have a long and pointed genital papilla, female adult fish have a shorter version that is blunt and yellow in color.
Dragon Fish Goby Appearance
One of the reasons that this goby species has been becoming more popular is its beautiful and unusual appearance.
Typical for the goby family, these fish have large heads, and an elongated body. But this elongation is especially pronounced in dragon gobies, leading some hobbyists to refer to them as ‘dragon eels’.
Healthy dragon fish gobies have a beautiful, iridescent metallic blue or violet upper body, with golden blotches. Less healthy fish may turn a pale gray color.
In pet stores, dragon fish gobies are usually around 3-5 inches in length, but they grow much bigger! In the wild, these large fish can grow up to 24 inches long, but they rarely exceed 15 inches in a fish tank.
Dragon Fish Goby Care Guide
Tank Size
Since dragon fish gobies typically grow to over a foot in length, adults should never be kept in tanks smaller than 4 feet long. This means aquariums with a capacity of at least 55 gallons.
Because they’re territorial towards each other and other gobies, it’s better to choose a tank of at least 90 gallons if you’re looking to keep a pair.
Substrate
One of the most important elements of a dragonfish goby tank setup is the right substrate. In their natural habitat, dragonfish gobies live in estuaries and bays with a sandy or muddy bottom and feed by sifting the substrate for anything edible.
This makes gravel substrates entirely unsuitable or even dangerous for these fish since it’s possible for gobies to choke on, or severely scratch themselves on, pieces of gravel.
Sand substrates are, therefore, the appropriate choice, and aquarium sand that contains aragonite will also help to maintain the neutral-alkaline water that these fish prefer.
Since they spend much of their time buried in the sand, you’ll need to fill your aquarium with substrate to at least 3-4 inches deep.
Tank Environment
Dragon fish gobies are largely nocturnal and will really appreciate some dense plants that they can hide among during the daytime.
Because they come from muddy or sandy habitats, it’s thought that this type of goby would rarely encounter rocks in the wild. Aquarists online have reported dragon gobies injuring themselves on abrasive rocks, dead coral, or stones with sharp edges, such as lava stone or slate.
On the other hand, rocky caves may help these fish to take cover and relax when they’re kept with semi-aggressive brackish water species like monos, and archerfish. If you do add rocks and stones, just make sure that they’re completely smooth with no sharp edges!
Also, make sure your tank has a good lid since these gobies have been known to make a bid for freedom and end up on the floor. They’ve even been known to push open a loose-fitting lid when they’re determined to escape! If you notice this behavior, test your water and consider what could be causing their wish to exit.
Water Salinity
The most important thing to understand about dragon fish gobies is that they’re brackish water fish that will neither feel at home in a freshwater aquarium nor in a marine setup.
While some sources report that they can acclimatize to freshwater or saltwater over a long period of gradual adjustment, brackish water experts like Neale Monk refute these claims. According to Monk, dragon gobies may merely survive freshwater for extended periods, but will never enjoy it.
So, whereas true marine aquariums typically have an ocean-like salt concentration of 35 parts per thousand, these fish prefer a salinity of around 8 parts per thousand or 1.005 SG (Relative Specific Gravity).
Water Parameters
Other than water salinity, you should keep dragon fish gobies in water that is neutral to alkaline with a pH of between 7.0-8.2. If you’re using a good quality marine salt mix, water pH and hardness should be taken care of automatically.
Dragon gobies are tropical fish and need stable water temperatures of between 74-82°F (75-77°F optimum) to remain happy. This means that a good aquarium heater with a reliable thermostat is essential for keeping dragon gobies in optimum health.
Filtration
Although dragon fish gobies sometimes inhabit muddy estuaries, that doesn’t mean that they can tolerate poor water quality. On the contrary, these fish demand very clean water and are highly susceptible to ammonia and nitrite poisoning.
This means you’ll need a reliable, efficient filtration system in your aquarium to keep them happy and healthy. Powerful hang-on-back (HOB) power filters can be suitable for tanks of up to 90 gallons, but for larger aquariums, you’re better off with a canister filter.
Clean the filter and test your water every two weeks to ensure that water quality is kept in optimum condition.
Feeding
Because dragon fish goby are usually caught in the wild, they may not be so quick to adapt to commercial fish foods.
In their natural habitat, these bottom-dwellers are sifting feeders, using their gills and tiny teeth to filter the substrate for edible morsels like invertebrates and algae.
You can allow them to feed in a similar way in captivity by offering them frozen foods that will quickly sink to the bottom without other fish eating them first.
Because these brackish fish are often nocturnal feeders, a good strategy for feeding them is to offer food after you turn the aquarium lights out. That way other fish will be less likely to eat the food before it sinks to the bottom for your almost-blind gobies to sniff out and guzzle down.
Blood worms, black worms, and tubifex worms are all good options. Sinking shrimp pellets, spirulina flakes, and algae wafers may also be accepted.
Compatible Tank Mates
Because they’re brackish water fish, dragon fish goby tank mates need to be compatible with a brackish water tank. Tank mates also need to be fairly peaceful, but large enough that they won’t get intimidated by your goby!
Possible candidates include sailfin mollies, archer fish, monos, orange chromide, and target fish.
While dragon fish gobies are relatively peaceful fish, and nearly blind, they can be territorial with other gobies and bottom-dwelling species.
Some sources suggest shrimps and snails as tank mates, but I’d be surprised if they’d survive long in the company of a fully-grown dragon goby!
Health and Disease
As we’ve already discovered, dragon fish gobies have rather delicate skin and fins that can easily get cut or damaged by sharp or rough objects in the aquarium (including gravel and dead coral).
If you spot any wounds on your fish, it’s especially important to take meticulous care of your water quality, make sure there’s enough salinity, and treat with antibiotics if a serious bacterial infection breaks out.
Dragon fish gobies are also quite vulnerable to ammonia poisoning, and poor water conditions in general. If you see them breathing quickly or gasping for air, chances are that your water quality or water parameters aren’t in the right range and are making your goby stressed.
For this reason, it’s important to test your water regularly to check that everything is satisfactory to meet the specific needs of these fish.
One last point is about feeding. While most aquarium fish are all too greedy and will more often suffer from overfeeding than underfeeding, dragon fish gobies are almost blind and need to wait for their food to sink to the bottom before they can eat.
If you don’t adapt your feeding regime for these specialized fish, they may not get enough food and become very thin. Extended periods of malnutrition could prove fatal.
Breeding Dragon Fish Goby
Breeding dragon fish in an aquarium is extremely challenging, to say the least. Almost all fish found in stores come from wild stocks, although successful captive breeding has been documented!
In Tropical Fish Hobbyist (#473), on pages 130-132, Harper reports that a single male should be kept with three females. The tank should have plenty of hiding places and the fish fed on a rich diet of meaty foods.
The male goby guards the nest but should be removed when the fry hatch. They can be fed on rotifers and “green water” containing algae, and later on baby brine shrimp.
A very large aquarium and much more in-depth research will be needed to breed this brackish species successfully!
Lifespan
When well-looked after, dragon fish gobies can live for over 10 years in captivity.
Sadly, mistreatment in pet stores, and being sold to underqualified fish keepers often results in them dying prematurely.
Tank Maintenance
Some top tips for keeping your dragon goby in tip-top condition!
- Feed dragon fish gobies a diverse, healthy diet that includes regular additions of algae and frozen foods.
- Get yourself a good filter and clean it every 2-3 weeks.
- Vacuum your substrate and make partial water changes of 15-35% every 1-2 weeks, with treated water of matching temperature and salinity.
- Get yourself a reliable heater and thermometer. Make daily checks to ensure the temperature is within the ideal range for all of your fish.
- Observe your fish closely every day to ensure they are in good health and interacting peacefully with each other.
- Test your aquarium’s water every two weeks, or any time your fish seem unwell.
Buying Guide
You won’t find dragon fish gobies in any old pet store, but they do pop up from time to time, and sometimes in surprising places. Tragically, you can even find reports online of people buying them in Walmart!
In reality, these specialized fish should never be bought on a whim. Setting up the right tank conditions for them requires proper preparation, forethought, and many years of fishkeeping experience.
FAQs
Are Dragon Gobies an Aggressive Fish?
Despite many reports that dragon gobies are an aggressive species, they tend to be remarkably peaceful with free-swimming fish.
The same cannot be said for their attitude towards each other. As I’ve pointed out, dragon fish gobies can be territorial with each other and other goby species, and may even bicker with other bottom-dwellers.
Can Dragon Gobies Eat Dry Food?
Since most dragon gobies found in the trade come from wild stocks, they may not learn to recognize commercial fish foods such as flake foods or fish pellets as food at all.
Algae wafers and spirulina seem to be more readily accepted, as do frozen foods that resemble this fish’s natural diet.
Final Thoughts
Keeping brackish water fish like the dragon fish goby is a level up from a freshwater setup and requires plenty of experience and know-how to get right.
If you’re serious about starting a brackish water tank, I’d thoroughly recommend reading an in-depth guide first, such as the highly acclaimed book by Neale Monks: Brackish-Water Fishes: An Aquarist’s Guide to Identification, Care & Husbandry.
