Species profile
True Rummy Nose Tetra
Petitella rhodostoma
Peaceful
Moderate care
100 L minimum aquarium
4–5 cm adult size
Midwater
Minimum group: 10
About this species
General notes for hobby use.
True Rummy-nose Tetra, now Petitella rhodostoma. A tight-shoaling soft-water fish that rewards stable mature conditions and clean water.
Water parameters
Suggested general range for long-term care.
Temperature
24–28 °C
pH
5.5–7
GH
Up to 10 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: 10
Tank zone
Midwater
Territory level
None
Predation risk
Shrimp fry
Bioload factor
0.6
One of the stronger schooling tetras. Keep a substantial group; colour and shoal tightness can fade when stressed or water quality deteriorates.
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
No
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Omnivore
Minimum aquarium volume
100 L
Minimum footprint
80 × 30 cm
Accepted scientific name
Petitella rhodostoma
Alternative names
True Rummy Nose Tetra, Rummy-nose Tetra, Petitella rhodostoma, Hemigrammus rhodostomus
Native range
Lower Amazon River basin and Orinoco River basin in South America.
Natural habitat
Soft acidic forest-water habitat. Use subdued lighting, wood/leaf-litter structure, excellent filtration and stable low-pollutant water.
Diet & feeding
Small omnivore/invertivore; use fine quality dry foods plus small frozen/live crustaceans and insect larvae.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Sexual dimorphism is subtle; mature females tend to be fuller-bodied, especially when carrying eggs.
Breeding
Egg-scattering non-guarder. Successful breeding normally requires very soft acidic water and protection of light-sensitive eggs from adults.