Knight Goby - Stigmatogobius sadanundio : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Knight Goby (Stigmatogobius sadanundio) is an exquisite bottom-dwelling fish well-suited for both brackish and freshwater aquarium setups. While not an ideal choice for novice aquarists, it offers a wealth of personality and provides an engaging experience for the more experienced fish keeper. These Gobies tend to be more active and visible during the day.
When selecting tank mates, it's important to choose species of a similar size and robust nature, especially those sharing the lower strata of the aquarium. Smaller fish may be at risk of being preyed upon by the Knight Goby. Conversely, overly aggressive or boisterous species should be avoided, as the Knight Goby generally exhibits a timid and shy demeanour. Optimal companions are those that inhabit the upper levels of the water, such as Rainbow Fish and Archer Fish, as they are less likely to encroach upon Knight Goby’s territory.
Knight Gobies may show aggression towards their own kind and are best housed singly. However, in a well-appointed aquarium with abundant rocky caves and crevices providing visual barriers, cohabitation of multiple specimens is possible. Adequate territorial space is essential to prevent aggression; a good rule of thumb is to provide at least two or three hiding places per fish.
The aquarium should feature a soft sand substrate or fine, smooth, rounded gravel, catering to the Knight Goby's preference for bottom-dwelling. Dim lighting is advisable, as these fish can be sensitive in well-lit environments. Low-light tolerant plants that can thrive in brackish conditions are suitable, as Knight Gobies pose no threat to vegetation. Meticulous attention to water quality is imperative, necessitating powerful filtration and a consistent maintenance routine. Additionally, a well-covered tank is essential to prevent these known jumpers from escaping.
Physically, Knight Gobies boast greyish-blue bodies with two distinct dorsal fins; the first has about six stiff rays with an elongated blackish spot, while the second mirrors the length of the long-based anal fin and features dark spots at the bases. Both sexes are speckled with black dots, adding to their striking appearance.
Knight Goby Photos
Sexual Dimorphism
Distinguishing between male and female Knight Gobies is a relatively straightforward process. Mature males are characterized by their elevated dorsal fins. In contrast, females generally exhibit a smaller stature, with a more rounded body shape and often display a yellowish hue in their body colouration compared to males. Additionally, the markings on females are typically less pronounced than those observed on their male counterparts, further aiding in identifying the sexes within this species.
Quick Facts
| Scientific Name | Stigmatogobius sadanundio |
|---|---|
| Year Described | 1822 |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Gobiiformes |
| Family | Oxudercidae |
| Genus | Stigmatogobius |
| Origins | Sri Lanka , Myanmar , Thailand , Cambodia , Malaysia , Singapore , Indonesia |
| Max Size | 9 cm |
| Temperament | Peaceful |
| Aquarium Level | Bottom - Middle |
| Difficulty | Intermediate |
| Shoaling | No |
| Best kept as | 1 Male + Several Females |
| Diet & Feeding | Omnivore |
| Reproduction | Cave Spawner |
| Average Lifespan | Up to 5 Years |
Water Parameters
| Water Type | Freshwater/Brackish |
|---|---|
| pH | 7.0 - 8.5 |
| GH | 10 - 20 |
| ℉ | 68 - 78 |
|---|---|
| ℃ | 20 - 26 |
Natural Habitat
The Knight Goby, a species native to coastal regions, has a distribution that extends from Pakistan eastward through the Indian subcontinent, encompassing Sri Lanka. In Southeast Asia, its presence is noted in the western half, including countries such as Myanmar, Thailand, Cambodia, Peninsular Malaysia, and Singapore. Additionally, this species is found in the coastal areas of Sumatra in Indonesia.
Habitually, these gobies are predominantly freshwater dwellers but are also known to inhabit brackish waters in estuaries and tidal zones of rivers. They exhibit a benthic lifestyle, often residing in shallow waters, sometimes mere centimetres in depth, demonstrating their adaptability to a variety of aquatic environments.
Breeding
Breeding Knight Gobies (Stigmatogobius sadanundio) within the aquarium hobby has been accomplished, although comprehensive documentation on the process remains limited. It is believed that these gobies employ cave spawning as their reproductive strategy. This involves a detailed and extended courtship display, culminating in the female laying as many as 1000 eggs on the interior roof of a chosen cave-like structure.
Consistent with the reproductive behaviours observed in many goby species, the male assumes the responsibility of tending to the brood post-spawning. This paternal care includes guarding and maintaining the eggs until they hatch. However, once hatching occurs, parental involvement typically ceases. Notably, the fry of Knight Gobies are exceptionally small and present significant challenges in terms of rearing, requiring specialized care and attention to ensure their survival and growth in a captive environment.
Diet & Feeding
The Knight Goby exhibits a diverse diet in its natural habitat and captivity. In the wild, this species feeds on various small invertebrates, including insect larvae, crustaceans, and zooplankton. This opportunistic feeding behaviour allows the Knight Goby to thrive in the fluctuating conditions of estuarine ecosystems.
In captivity, replicating this natural diet is key to maintaining the health, vitality and longevity of these fish. A balanced diet should include a mix of high-quality flake or pellet foods supplemented with live or frozen foods such as brine shrimp, daphnia, and bloodworms. These not only provide the necessary nutrients but also encourage natural foraging behaviours.
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