Species profile
Peacock Eel
Macrognathus siamensis
Peaceful
Moderate care
280 L minimum aquarium
20–32.5 cm adult size
Bottom
Minimum group: 5
About this species
General notes for hobby use.
Sociable for a spiny eel; Fishkeeper recommends groups of five or more when space allows.
Water parameters
Suggested general range for long-term care.
Temperature
24–28 °C
pH
6–7
GH
2–15 dGH
KH
Not yet documented
Flow preference
Low–moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 5
Tank zone
Bottom
Territory level
Low
Predation risk
Small fish
Bioload factor
2.5
Shy and generally peaceful, but adults will eat small fish and shrimp.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
No / caution
Snail safe
Yes
Cave breeder
No
Digs substrate
Yes
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Carnivore
Minimum aquarium volume
280 L
Minimum footprint
120 × 45 cm
Accepted scientific name
Macrognathus siamensis
Alternative names
Peacock Spiny Eel
Native range
Cambodia, Laos, Thailand and Vietnam in Mekong, Chao Phraya and related drainages.
Natural habitat
Slow vegetated rivers and swamps. Fine sand is essential for burying; use shaded cover and a tightly sealed 120 cm+ aquarium.
Diet & feeding
Frozen/live worms, insect larvae, crustaceans and quality carnivore sinking foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Mature females may appear fuller-bodied; otherwise difficult to sex.
Breeding
Home-aquarium breeding is rare and poorly established.