Gobiidae. Subfamily: Gobionellinae
Widely distributed around the Southern USA, Central America, the Caribbean islands and north eastern South America. It’s been recorded in the USA, Mexico, Belize, Guyana, French Guyana, Venezuela, Colombia, Brazil, Cayman Islands, Turks Caicos, Cuba, Haiti, Dominican Republic, Jamaica and Puerto Rico.
Inhabits estuarine areas, where it tends to congregate above muddy substrates. It is also often seen in freshwater and in open water off estuaries.
Maximum Standard Length
25″ (62.5cm), although usually smaller in captivity.
Aquarium SizeTop ↑
48″ x 24″ x 24″ (120cm x 60cm x 60cm) – 450 litres, although even this may not be adequate should it reach its full potential. Juveniles can be grown on in smaller tanks.
This species requires brackish water at least 1/4 the strength of marine water (preferably between 1.005-1.015 sg). The substrate should consist of several inches of soft sand, as it likes to spend a lot of time at least partially buried. Other hiding places and decor can be in the form of bogwood, smooth rocks and lengths of plastic tubing for the fish to hide in.
Temperature: 73-79°F (22-26°C)
Feeds mainly on filamentous algae and detritus in nature, filtering these small morsels out of its turbulent, nutrient-rich natural waters. Feeding newly-imported specimens can therefore be problematic. Most eventually learn to accept frozen and live foods such as bloodworm, brine shrimp, tubifex etc. and pieces of algae wafer, nori sheets or spirulina flakes. The provision of vegetable matter is absolutely essential for the long term well-being of the species.
Behaviour and CompatibilityTop ↑
Although it is often sold as such, the violet goby is completely unsuitable for the general community tank. It can however be kept with other peaceful brackish species, and although it is territorial will not eat even the smallest of tankmates. Do not keep it with very vigorous or aggressive species, as it will be easily out-competed at feeding time. It is somewhat belligerent towards its own kind, and a very large tank would be required to keep a group long term.
Difficult to sex by external means. The only reliable method known at present is to examine the genital papillae of the fish. That of the male is pointed and long, whilst of the female is short, blunt and yellow in colour.
Not thought to have been achieved in captivity.
This fish is also commonly sold as the dragon or Peruvian goby, or dragon fish, and its bizarre appearance has made it popular in the trade. This is unfortunate, as not only does it grow very large, but it has specialised feeding requirements and does not survive for very long in freshwater. When provided with the correct conditions, however, it makes a unique and fascinating captive subject. There is a smaller species in the genus, G. peruanus, that does survive in freshwater, being a riverine fish in nature. It is actually this species that is more commonly sold in the UK, despite usually being imported as broussonnetii. Conversely, the true broussonnetii is the species often sold in US stores as a freshwater species! Peruanus can be distinguished by its smaller adult size (maximum length of around 18″), and thicker, more purple coloured body.