Stigmatogobius sadanundio (Knight Goby )

Stigmatogobius sadanundio

Common Name: Knight Goby, Grey Knight Goby
Origin: Southeast Asia (India, Sri Lanka, Indonesia)
Size: Up to 9 cm (3.5 inches)
Temperament: Semi-aggressive
Tank Level: Bottom-dweller
Care Level: Moderate

Species Overview

The Knight Goby (Stigmatogobius sadanundio) is a striking and inquisitive goby species native to the estuarine and freshwater habitats of Southeast Asia. Popular in the aquarium trade for its graceful movements and bold personality, this goby boasts a silver base color adorned with dark spots and a vivid bluish blotch at the base of its dorsal fin.

Knight Gobies are micropredators in the wild, known for darting quickly across the substrate in search of small invertebrates. With proper care, they make a hardy and captivating addition to freshwater or lightly brackish aquariums.

Appearance & Sexual Dimorphism

• Body Coloration: Pale silver or grayish-white with scattered dark maculations (spots)

• Fins: Elongated dorsal fin; rounded caudal fin

• Male Characteristics: Slimmer bodies, greyer coloration, and more extended dorsal fin rays

• Markings: Both sexes feature a blue or bluish blotch at the base of the first dorsal fin

Natural Habitat

Knight Gobies are found across India, Sri Lanka, and Southeast Asia, often inhabiting estuaries, tidal creeks, slow-moving rivers, and brackish waters. Though adaptable to both fresh and brackish water, they tend to thrive in slightly brackish conditions.

Aquarium Care

Tank Size: 20 gallons minimum for a small group
Substrate: Sand or fine gravel
Decor: Plenty of hiding places such as driftwood, rocks, PVC caves, and dense plants
Water Movement: Gentle to moderate flow
Lighting: Moderate

Water Parameters

• Temperature: 22–28°C 

• pH: 7.0–8.5

• Hardness: Moderate to hard

• Salinity: Can be kept in freshwater but will benefit from light brackish conditions (e.g., 1.002–1.005 SG)

Note: Adding a small amount of marine salt mix can help mimic natural conditions and boost overall vitality.

Diet

Knight Gobies are micropredators, feeding on small invertebrates in the wild. In captivity, they readily accept a range of meaty foods:

• Live or frozen bloodworms, daphnia, brine shrimp

• High-quality sinking pellets and carnivore granules

• Chopped earthworms or insect larvae

• Occasional flake food (though they prefer sinking foods)

Behavior & Compatibility

Temperament: Generally peaceful, but may become territorial—especially toward their own kind or other bottom dwellers.
Activity: Active and alert, often seen perching, darting, or sifting through substrate.

Tankmates Suggestions:

• Small peaceful to semi-aggressive species (e.g., mollies, platies, glassfish)

• Avoid slow, timid, or long-finned fish

• Avoid shrimp and very small fish—they may be seen as prey

• Best kept in groups of 3–5 in spacious tanks to reduce intraspecific aggression

Breeding

Breeding Stigmatogobius sadanundio in captivity is possible but uncommon. They are cave spawners, with males guarding the eggs until they hatch. A slightly brackish environment, warm temperatures, and secluded spawning sites (such as small caves or half-coconut shells) may encourage breeding behavior.

Quick Facts

• Personality: Curious, bold, and responsive to surroundings

• Versatility: Adapts well to both freshwater and brackish conditions

• Feeding: Carnivorous, needs protein-rich diet

• Ideal Setup: Aquariums with gentle flow, hardscape hiding areas, and room to explore