A considerable number of goby species are available to aquarists. While the majority of this huge group is marine, there nevertheless is a diversity of interesting gobies that can be kept in freshwater or brackish aquaria. Peaceful (at least in their interaction with other species) and small, they are an excellent choice for the so-called community aquarium. On account of their diminutive size, they often may be kept in nano aquarium systems. They are generally quite hardy and undemanding when kept under proper conditions. Optimal conditions vary between species. The following is a sampling of care requirements for some of the most important freshwater aquarium gobies in the trade.
- Bumblebee goby
- Knight goby
- Dragon goby
- Cobalt goby
- Marbled goby
Bumblebee goby (Brachygobius xanthozona)
Two species have been seen in the trade as bumblebee gobies, the “true” bumblebee Brachygobius xanthozona and a related species (B. nunus) that otherwise goes by the name golden banded goby. While both species are best suited to brackish conditions, the former is highly tolerant of freshwater while the latter is not. The true bumblebee can be distinguished by its unbroken black bands.
A native of Thailand and Vietnam, B. xanthozona reaches a length of about two inches. It very much prefers at least a little bit of salt (perhaps the small “tonic” dose suggested for most freshwater fishes). It prefers a temperature of 77-86°F and a pH of 7.5-8.5. The aquascape for bumblebee gobies should include plenty of wood and stone; if multiple specimens are to kept, provide adequate space for the establishment of individual territories.
Be ready to use live feed (e.g. artemia) in the event this finicky eater is slow to adapt to a prepared diet.
Knight goby (Stigmatogobius sadanunidio)
The knight goby comes from the estuaries of India to Indonesia. As such, it is considered to be a primarily brackish water species. While it is thought by many to be very tolerant of freshwater, it is best kept in water that has at least a little salt in it. It is imperative, however, to keep the water hardness high (to 25°dH). It prefers a temperature of 68-79°F (ideally with day/night fluctuations of a few degrees) and a pH of 7.5-8.0. Its aquascape should be rocky with a sandy substrate and include plenty of nooks and crannies to hide in. It is said to be skittish under bright lighting. Males have longer fins and less yellowish coloration than females.
Dragon goby (Gobioides broussonnetii)
While aptly named for the reason of its physical appearance, the dragon goby is actually a rather timid fish. As such, it should be kept only with peaceful tankmates. Multiple dragon gobies, however, can only be kept together in very large aquaria as they are highly territiorial. Even in the murky, turbid waters of muddy estuaries of the subtropical west Atlantic, it feels most comfortable in the dark of night. This nearly blind species is primarily nocturnal and should be fed after the lights are down.
It is rather large for a goby, typically growing to a length of one to two feet in captivity. This should be taken into consideration when observing the tiny juveniles usually offered at aquarium shops. Examine any specimen carefully (especially the skin and fins) before any purchase, as the species is susceptible to bacterial infection.
Dragon gobies feed heavily on detritus that they filter out of the substrate. Very fine substrates or mud are therefore highly suggested for the species. It will scrape some algae from the rocks and glass. A variety of foods such as frozen bloodworms and sinking pellets is best for this omnivore. It prefers a temperature of 74-78°F, a pH of 7.0-8.5 and a specific gravity of 1.006-1.008.
Cobalt goby (Stiphodon semoni)
Like other members of its genus (30 in all), the cobalt goby is highly prized by some aquarists on account of the attractive neon markings on mature males. It is fairly small even for a goby, rarely exceeding a couple of inches.
The cobalt goby originates in coastal streams of central Indonesia and perhaps all the way to the Solomon Islands and Papua New Guinea. In its native habitat, it is more likely to occur with small inverts such as shrimps and snails than with other fishes. It prefers clear, clean, fast-moving, well-oxygenated water; frequent and substantial water changes (perhaps 30-50% weekly) are required. Provide a gravel substrate with larger cobbles and stones. Ideally, algae, bacteria and other associated organisms should be allowed to cover the rocky surfaces; this provides a natural and ready food source for these gobies, which are primarily biofilm grazers (meaty foods should be avoided for the sake of their specialized digestive systems). Strong lighting will encourage biofilm development. Algae wafers can be used for supplemental feeding. It prefers a temperature of 75-82°F, a pH of 6.5-7.5 and a hardness of up to 15°dH.
Marbled goby (Oxyeleotris marmorata)
The marbled goby is enormous for a gobioid fish, reach a length of one to two feet. It can be found in various types of fresh and brackish water bodies across Southeast Asia. It prefers sluggish water movement, a temperature of 72-80°F, a pH of 6.5-7.5 and a hardness of 10-15°dH. It prefers freshwater but easily tolerates some salt.
It is also a voracious predator. Its diet can consist primarily of meaty foods such as prawns, silversides and earthworms. Take care to carefully control feeding portions, as it potentially can overeat. Do not keep it with any tankmates that are small enough to swallow whole.
Certainly for a goby, O. marmorata needs a lot of space—around 120- to 150-gallon tank minimum. If using bright lighting, provide shady hiding spaces, as it is primarily nocturnal. There should be an abundance of wood and stone in the aquascape. Without sufficient cover from a rocky cave, sunken log, bushy plant, etc., it may attempt to bury itself in the substrate. Take care when introducing multiple individuals, as it is territorial with its own kind. Males can be distinguished from females by extensions on the dorsal and anal fins.