Knight Goby

Stigmatogobius sadanundio

Gobies & Gudgeons

A distinct, high-bodied goby found in estuaries across South Asia. Unlike most bottom-dwelling gobies, the Knight Goby frequently hovers in the water column. While often sold as freshwater fish, they thrive best in slightly brackish water (SG 1.003-1.005) or very hard, alkaline freshwater. They are territorial and notorious fin-nippers, making them poor tankmates for Guppies or Bettas.

At a Glance

Adult Size9 cm
Body ShapeFusiform
Growth RateModerate
TemperamentSemi-Aggressive
Water TypeBrackish Tolerant
Flow PreferenceModerate
Waste OutputMedium
StockingSolo or group

Tank Requirements

Minimum Volume75 L
Minimum Length60 cm
FlowModerate
Water TypeBrackish Tolerant
Must-Haves in the Tank
Sand (Sifters)Shells (Breeding/Hiding)Driftwood (Digestion/Hiding)

Water Parameters

Temperature2028°C
pH78.5
Hardness1030 dGH

Temperament & Compatibility

Aggression LevelSemi-Aggressive
6/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least1 (solo is fine)
Max per TankNo limit
Can Live Alone?Yes
Behavior Traits
Fin NipperShrimp EaterFry PredatorTerritorial (Defends specific area)Digger (Disturbs Substrate)Aggressive to same species/look-alikes

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The standard wild-type form. Males typically have longer, more pointed fins and a lighter grey body compared to the yellowish, smaller-finned females. Best kept singly or in a mated pair; groups require large tanks to prevent territorial fighting.

Differs in 1 trait from base species

Behavior Traits
Fin NipperShrimp EaterTerritorial (Defends specific area)

Knight Goby Care Summary

The Knight Goby, scientifically known as Stigmatogobius sadanundio, belongs to the Gobies & Gudgeons family group. Adults reach a maximum size of approximately 9 cm and have a fusiform body shape with a moderate growth rate. Classified as semi-aggressive, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a medium level of biological waste.

To thrive, the Knight Goby requires a brackish tolerant aquarium with a minimum volume of 75 litres and a tank length of at least 60 cm. Water temperature should be maintained between 20°C and 28°C, with a pH range of 78.5 and a general hardness of 1030 dGH. A moderate water flow is preferred. To replicate their natural habitat, the tank should include sand (sifters), shells (breeding/hiding), and driftwood (digestion/hiding).

Knight Goby can be kept singly or in a group, making them flexible additions to most setups. Keepers should be aware that this species may nip the fins of slow-moving or long-finned tankmates, is not safe with ornamental shrimp, can be aggressive toward its own kind, and will defend a territory within the tank. The Knight Goby is typically available in one standard form.


Similar Species

Peacock Gudgeon

Tateurndina ocellicauda

Gobies & Gudgeons
6 cm Peaceful

A stunning, peaceful freshwater sleeper goby from Papua New Guinea. Known for their vibrant blue, red, and yellow colors, they are excellent nano-tank inhabitants. They are not true gobies (they lack fused pelvic fins) and are exclusively freshwater. They prefer slow-moving water, dense vegetation, and small caves (like PVC pipes or smooth stones) for spawning.

Neon Blue Goby

Stiphodon atropurpureus

Gobies & Gudgeons
5 cm Mostly Peaceful

A stunning, specialized freshwater goby native to fast-flowing hill streams in Asia. Males display brilliant neon blue metallic coloration, while females are striped. They are specialized biofilm grazers ('Aufwuchs' eaters) and require mature tanks with established algae/biofilm stones. They are obligate stream dwellers requiring high oxygen and strong flow.

Bumblebee Goby (Brackish)

Brachygobius xanthozonus

Gobies & Gudgeons
4.5 cm Mostly Peaceful

A miniature, bottom-dwelling goby famous for its striking black and yellow stripes. While they are often sold as freshwater fish and can survive in it temporarily, they are highly susceptible to fungal infections in fresh water and truly require a brackish setup (SG 1.002-1.005) to thrive long-term. They are notoriously picky eaters, often ignoring flakes in favor of live or frozen foods (like bloodworms or brine shrimp).

Empire Gudgeon

Hypseleotris compressa

Other
12 cm Mostly Peaceful

A remarkably adaptable and beautifully colored sleeper goby (not a true goby) native to Australia and New Guinea. They inhabit both pure freshwater streams and brackish estuaries. While generally peaceful and excellent community fish, they are micropredators that will happily consume dwarf shrimp and very small fry.

Violet Goby (Dragon Goby)

Gobioides broussonnetii

Gobies & Gudgeons
50 cm Peaceful

Often misunderstood due to its terrifying 'Dragon' appearance and sharp teeth, the Violet Goby is actually a gentle, nearly blind scavenger and filter feeder. It uses its teeth to scrape algae, not to bite fish. It requires brackish water to thrive long-term and fine sand to sift through for food. It is not a predator.

Green Spotted Puffer (Brackish)

Dichotomyctere nigroviridis

Puffers
15 cm Highly Aggressive

The Green Spotted Puffer is a highly intelligent but notoriously aggressive fish. While frequently (and incorrectly) sold as a freshwater species, they strictly require brackish water that increases in salinity as they mature, eventually needing high-brackish or full marine conditions as adults. They have beak-like teeth that grow continuously and must be worn down by a diet of hard-shelled foods. Best kept entirely alone.