Not furry, but we like them anyway.

Knight Goby

Stigmatogobius sadanundio

Also called Knight goby, Gobius sadanundio (older name)

SpeciesShort profile

From South and Southeast Asia, from India, Sri Lanka and the Andaman Islands east to Singapore and Indonesia, mainly in fresh water but also in estuaries and tidal river zones1 2 3

At a glance the quick version

Length9 cm1 3 2

Sizesmall

Handsome spotted pattern with tall fins on males

Easy to feed and accepts most foods

Devoted parents that guard their eggs

3 2 1

Looks how to spot one

Scaled goby

A sturdy, grey-blue goby dotted with dark spots, with two dorsal fins that also carry spots. Mature males grow taller dorsal fins and longer fins overall, while females are smaller, rounder and have a yellowish tint.2 3

Coloursgrey-blue to silvery greyblack spotsyellowish tones in females2 3

Personality what they are like

Confident and territorial, especially near the bottom. It is a keen predator that will try to eat anything small enough to fit in its mouth, so it suits a tank of similar-sized or larger fish.3 2

Daily activity how busy a day looks

A bottom-oriented fish that likes to claim a cave or rock as home base and patrol its patch.2 3

Grooming and care the hands-on bits

Keep at about 20 to 26 C, pH 7.0 to 8.5 and hard water (10 to 20 dGH). It does well in fresh water but also enjoys light brackish conditions around SG 1.005. Wikipedia notes it likes subdued lighting.3 1 2

Home where they are happiest

Seriously Fish recommends a tank with a base of at least 75 x 30 cm (around 68 litres), with rocks, caves and clear territory boundaries.3 2

Food basics what goes in the bowl

An unfussy eater that takes dried, frozen and live foods. In the wild it hunts small aquatic animals such as mosquito larvae, and it also appreciates some vegetable matter.3 1

Company who they like around

Wikipedia advises keeping it singly because of its territorial nature. Good companions are mid-water fish of similar size, such as archerfish, chromides, rainbowfish, swordtails or sailfin mollies, rather than other bottom dwellers.3 2

The story where it all began

Francis Hamilton described the knight goby in 1822 from Indian waters. Its genus has been trimmed over the years from 18 to about 7 species, and this remains the member most often seen in the aquarium hobby.1 2 3

Fun facts for the dinner table

1
A breeding pair can produce up to about 1,000 eggs, stuck to the ceiling of a cave.1
2
The fry are fairly easy to raise on newly hatched brine shrimp, making it a rewarding species to breed.2
3
Despite being sold as a brackish fish, it is found more often in fresh water than in brackish water in the wild.3
4
Wikipedia notes it benefits from a small daily rise and fall in water temperature.2

Recognised by the official bits

IUCN Red List: Least Concern (assessed 2024)1

The care rhythm a typical week and year

A typical home-care rhythm for a Knight Goby. A starting point, not a vet's advice.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Salinity checkBrackish fish need a little marine salt, and some need more as they growevery week
Water changeAbout 25% of the water, mixed to the same salinityevery week
Water testevery week
Filter rinseRinse in old tank water, never tap waterevery month

Owner questions the things everyone asks

How often should I feed my Knight Goby?

Furry Diary's starting plan is to feed small amounts once or twice a day. This unfussy eater takes dried, frozen and live foods, so you can vary its diet. Always check the food label and ask your vet for exact amounts.3 1 Pet Wiki plan

What does a Knight Goby eat, and what should it never eat?

It enjoys dried, frozen and live foods like mosquito larvae, plus some vegetable matter. Never feed anything too large to fit in its mouth, as it is a keen predator that will try to eat small tank mates.3 1

How much space does a Knight Goby need?

Seriously Fish recommends a tank with a base of at least 75 x 30 cm, around 68 litres. Provide rocks and caves to create clear territory boundaries for this bottom-oriented fish.3 2

What temperature, light or water does a Knight Goby need?

Keep water at 20 to 26 C, pH 7.0 to 8.5, and hard water (10 to 20 dGH). It enjoys fresh water or light brackish conditions (SG 1.005) and prefers subdued lighting.3 1 2

How often should I clean a Knight Goby's home?

Furry Diary's plan suggests a weekly 25% water change, mixed to the same salinity, and a monthly filter rinse in old tank water. Test water weekly and check temperature daily. Pet Wiki plan

Can a Knight Goby live with others?

It is best kept singly due to its territorial nature. Good companions are mid-water fish of similar size, like archerfish or rainbowfish, not other bottom dwellers.3 2

How long does a Knight Goby live?

Lifespan varies depending on care and environment. For specific information, please ask a good breeder or an exotic-pet vet.

Can I handle a Knight Goby?

It is best not to handle this fish, as it is a delicate aquatic creature. Enjoy watching it patrol its territory from outside the tank.

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

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Where this comes from

Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.

FishBase: Stigmatogobius sadanundio fishbase.seused for size, environment, water parameters, IUCN status, breeding, describer
Wikipedia: Stigmatogobius sadanundio en.wikipedia.orgused for description, aquarium notes, breeding, fun facts
Seriously Fish: Stigmatogobius sadanundio seriouslyfish.comused for distribution, water parameters, tank, diet, compatibility, sexing, taxonomy

Checked 2026-09-30. Text is written in our own words from these sources.