Furry Diary

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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 zones123

At a glance the quick version

Length9 cm132
Sizesmall
Handsome spotted pattern with tall fins on males
Easy to feed and accepts most foods
Devoted parents that guard their eggs
321

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.23

Coloursgrey-blue to silvery greyblack spotsyellowish tones in females23

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.32

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.23

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.312

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.32

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.31

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.32

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.123

Fun facts for the dinner table

  1. 1

    A breeding pair can produce up to about 1,000 eggs, stuck to the ceiling of a cave.1

  2. 2

    The fry are fairly easy to raise on newly hatched brine shrimp, making it a rewarding species to breed.2

  3. 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. 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 Furry Diary remembers it for you

A typical home-care rhythm for a Knight Goby. It is our own starting plan, not a vet's advice, and you can change every line in the app.

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Where this comes from

Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.

  1. FishBase: Stigmatogobius sadanundio fishbase.seused for size, environment, water parameters, IUCN status, breeding, describer
  2. Wikipedia: Stigmatogobius sadanundio en.wikipedia.orgused for description, aquarium notes, breeding, fun facts
  3. 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.