Gobies for the Freshwater and Brackish Tank
Author: Joshua Wiegert
Freshwater and brackish goby species are not nearly as numerous as their marine cousins, but many of them are well suited to captivity. As long as you provide the environment they need, these comical little fish will perform their antics in your tank for years to come.
The goby family, Gobiidae, is one of the largest families of fishes, containing over 2,000 species. The vast majority of these species are marine, although a few species can be found in brackish and even freshwater regions. Until very recently, very few of these non-marine species ever made it into the aquarium hobby, but several new species have begun to appear in retail shops. Personally, I don’t like letting the saltwater people have all the fun (they already get protein skimmers!), so let’s take a look at some of the various gobies that the rest of us can keep.
The vast majority of the so-called freshwater gobies are actually brackish (not all, just most). Brackish fishes are ones that live in areas of varying salinity, often estuaries, where marine and fresh waters can mix freely. The salinity in these regions can vary seasonally, or even hourly.
In the aquarium, these fishes tend to do best with a touch of marine salt in their water. Generally they are maintained at a specific gravity of 1.010 or less, with a value of 1.004 usually cited. This salinity can be achieved by mixing roughly a cup of marine salt with 5 gallons of water. Marine salt differs significantly from table salt or even road salt; it contains many other minerals, beyond sodium chloride, that are necessary for the health of brackish (or marine) fishes. The precise salinity doesn’t matter much, nor do minor fluctuations over time, but these brackish-water fishes will not thrive in pure fresh water.
Lastly, there are a large number of fishes available under the common name “goby” that are simply not members of the Gobiidae family. Many of these are freshwater or brackish-water fishes, including the “butterfly goby” or waspfish (Neovespicula depressifrons), various species of loaches and catfishes, and the sleeper gobies (in the family Eleotridae). The sleeper gobies are very closely related and will be discussed here; the others, which are simply misnamed, will not.
For a long time, the bumblebee goby was “the” goby in the hobby. In recent years, it has actually become somewhat hard to find. Bumblebee gobies (Brachygobius spp.) have black and orange stripes on them, similar to a bumblebee. They are brackish-water species that will generally deteriorate in fresh water.
The bumblebees comprise several closely related and similar-appearing species. Most of them grow to about 2 inches or so. In the aquarium, they make intriguing specimens, constantly bouncing around and clinging to surfaces, including the side of the tank.
They should not be kept with larger species that may pester or bother them. Being slow movers, they should also not be kept with active, fast-moving species (e.g., danios) that will outcompete them for available food. It may be difficult to train them to accept prepared foods. Live brine shrimp and blackworms may be necessary at first, with a transition to frozen foods. Eventually, they may take flakes.
The dragon or violet goby (Gobioides broussonnetii) is one of the strangest looking fish you’ll likely encounter. Shaped roughly like an eel, it has a serrated dorsal fin and translucent violet splashes on its sides. Tiny, beady eyes perch above a huge head. Despite the somewhat fearsome appearance, the dragon is quite peaceful.
It is, unfortunately, another brackish-water fish that is often kept in pure freshwater, which leads to its untimely demise. Believe it or not, dragons are North American natives, found from about South Carolina down to Brazil in coastal estuaries. Here they may be found buried in sand or mud, sifting through it for food.
These fish can be incredibly hard to feed in the aquarium, and my personal advice is to leave them in the estuaries. They are nearly blind (those beady little eyes are pretty useless) and have a great deal of trouble competing for food. They eat fine foods sifted both from the water column and from the substrate. Their poor eyesight means that they essentially have to be target fed, and all too often, they simply starve in the aquarium. They can be successfully fed by literally dropping food on top of them: They seem to figure it out when food hits them in the face! Thawed frozen brine shrimp, bloodworms, and the like can be squirted at them from a turkey baster, or chunks of beefheart or other frozen foods can be dropped directly in front of them.
The knight goby (Stigmatogobius sadanundio) is another of the classic gobies, having been in the hobby for many years. It is a striking fish with beautiful finnage, if not particularly colorful. Unlike the previous gobies, it can survive in fresh water quite well and is often found in pure freshwater habitats in the wild, although it will survive in brackish waters. Further, it has a voracious appetite and will eat any food offered to it. Unfortunately, despite the fun of the names, they cannot be kept with dragon gobies due to the differing water needs and the dietary problems.
They seem to prefer hard, alkaline water and suffer if the pH is below about 7.4. Knight gobies are also rather territorial; unless you have a fairly large tank, keep only one. They can make interesting tankmates for less-aggressive African cichlids, such as the various dwarf Tanganyikan cichlids.
The Desert Goby
The desert goby (Chlamydogobius eremius) is a fairly new import showing up from Australia. It is also the first of our true freshwater gobies, being found in desert pools, where it feeds heavily on aquatic crustaceans, insect larvae, and algae, filling a similar niche to the desert pupfishes. It is a striking olive color, with bright finnage highlighted in black and blue.
Best of all, it is easy to keep and breed! When in breeding condition, the olive deepens to a golden yellow and the fins become vibrant. The males have a larger head than the females and are a bit more slender and quite a bit more colorful. They are a cave-spawning species that will lay eggs beneath rocky overhangs and similar constructs, such as clay flowerpots, in the aquarium.
Desert gobies are bottom-dwelling fish that will do best in a shallow tank. They seem to enjoy coming up to the surface for a gulp of air, and without a swim bladder, this can be a serious trek in a deep tank. Water conditions don’t seem to be particularly important: They can be found in water as soft as rain to so hard you can bounce quarters off it. Provided nutrient levels are kept fairly low, they’ll do just fine. They will eagerly eat anything offered, including algae wafers, earthworms, blackworms, and many frozen or other prepared foods.
The algae gobies are small gobies apparently from Central Africa. They are being described by online sellers as a Sicydium species, and may be S. brevifile. The genus Sicydium contains several species found throughout the New World, including two in North America and a few found in Africa—definitely a widespread genus. Of course, there is the strong possibility that those being imported are completely undescribed species: A number of new gobies are being described frequently.
S. brevifile is a mostly black fish with reddish-orange tiger stripes on it, giving it a striking appearance. It is an ideal planted-tank resident and gobbles down hair algae. Its small size and bottom-dwelling antics make it an interesting alternative to larger cyprinids, such as the various flying foxes.
In addition to algae, small live foods should be provided until this fish transitions to frozen foods. As far as I’m aware, breeding has not yet been accomplished in the aquarium and, depending on what species is actually being imported, may be extremely difficult. Many species of Sicydium spawn in the pools of fast-moving streams, which their larvae gradually ascend, moving back down as adults. This is an incredibly difficult situation (but not impossible) to mimic in the aquarium.
The freshwater neon goby or cobalt goby (Stiphodon atropurpureus) bears a rather good resemblance to its more famous cousin. It is native to Eastern Asia, where it can be found in slightly brackish and even fresh water. It is a fairly small fish, reaching roughly 2 inches or so in the aquarium. It can be somewhat difficult to feed, owing to its small size, and may require small live foods, such as Daphnia, dero worms, and brine shrimp at first. However, it should eventually transition to frozen foods.
A handful of other Stiphodon spp. are appearing from time to time in the hobby nowadays, and all can be maintained similarly. Be sure to check into water quality needs: Some of these fishes are brackish water, and some are even marine! These are very colorful, beautiful fishes. All of these may require live foods at first and will also benefit greatly from algae in their diet, including spirulina wafers.
The Sleeper Gobies
Many types of sleeper gobies make it into the aquarium hobby with some degree of frequency. These are not true gobies but, instead, are contained in the closely related Eleotridae family, lacking the cup-like anal fins of the true gobies.
The sleepers are an interesting group of fishes. Some types move from freshwater to marine habitats as they mature, and others simply seem to occur across the board. Several species are actually native fishes.
They are all hardy, though they are essentially little more than a stomach with fins; anything they can stuff in their mouths will be stuffed in, eagerly. And anything they can’t stuff in their mouths, they will try. A word of warning: The sleepers available in the hobby get big, frying pan big. Be sure to investigate exactly which species is being sold as a “sleeper goby” and its eventual maximum size, and be prepared for this. Also, be sure to investigate whether the adult fish will survive in fresh or even brackish water: You may wind up with a big, ugly mouth to feed that requires a marine aquarium.
The most commonly encountered sleepers are those of the genus Dormitator. These are often sold as 3- or 4-inch-long juveniles that will quickly grow to rather large sizes. The marbled goby (Oxyeleotris marmorata) is also commonly sold at similar sizes: Be aware that this fish can reach over 2 feet in length.
Lastly, the crazy fish (Butis butis) is sometimes encountered. It is named for its bizarre behavior of hanging upside down in the aquarium. Twirling behavior may be seen, as well, but I believe this is a stress behavior from insufficient hiding places in the aquarium. They require lots of cover in the aquarium, or they will simply freak out and may jump. Crazy fish are a brackish-water species and can even handle straight salt water. They don’t seem to do particularly well in fresh water. They are definite predators and will hang upside down along rock edges or even the side of the aquarium waiting for a tasty morsel, such as a molly, to come by. They will also eagerly devour meaty prepared foods. This is a smaller sleeper, reaching only about 6 inches or so.
Despite the predatory nature of the sleepers, they are not able to hold up against more aggressive fishes, such as cichlids or nastier barbs. Keep them with more peaceful, big-bodied fishes, such as gouramis or giant danios, or with less aggressive types of cichlids. Most of our brackish-water fishes, such as monos, scats, archers, etc., will also fit the bill.
Try a Goby
Gobies are one of the most diverse groups of fishes, found throughout the world in both marine and freshwater habitats. They are playful, antic-filled fishes that fill the bottom niche of the aquarium. While several easy-to-find brackish-water fishes have been in the hobby for some time, several new freshwater ones are beginning to appear, and this article mentions only a few. Finding them can be somewhat of a challenge, although several online retailers and auction sites feature freshwater gobies.
If you're lucky enough to find any true freshwater gobies, be sure to give one of them a try for your aquarium. Don't let those salt creeps have all the fun.