Species profile
Zodiac Loach
Mesonoemacheilus triangularis
Peaceful
Moderate care
120 L minimum aquarium
7–9 cm adult size
Bottom
Minimum group: 6
About this species
General notes for hobby use.
Treat as a stream fish, not a generic warm stagnant tropical loach. Oxygenation and clean substrate matter.
Water parameters
Suggested general range for long-term care.
Temperature
20–25 °C
pH
6–7.5
GH
3–12 dGH
KH
Not yet documented
Flow preference
High
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 6
Tank zone
Bottom
Territory level
Low–moderate
Predation risk
Tiny fry
Bioload factor
1.5
Active stream loach. Keep a social group with abundant rock/wood refuges and strong oxygenation; individuals may squabble over favourite crevices.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
No / caution
Snail safe
Yes
Cave breeder
Yes
Digs substrate
Yes
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
5–8 years
Diet type
Omnivore
Minimum aquarium volume
120 L
Minimum footprint
90 × 35 cm
Accepted scientific name
Mesonoemacheilus triangularis
Alternative names
Zodiac Loach, Nemacheilus triangularis
Native range
Western Ghats, Kerala, southern India.
Natural habitat
Cool-to-warm hill streams with rock, gravel, leaf litter, current and high dissolved oxygen.
Diet & feeding
Benthic insect larvae, worms, crustaceans and some algae/detritus; use sinking foods plus frozen/live invertebrates.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Sexual dimorphism is subtle; mature females are generally fuller-bodied, while males may remain slimmer and show stronger breeding condition.
Breeding
Captive breeding is uncommon and reliable species-specific protocols are limited; seasonal environmental cues are likely important.