Species profile
Redtail Splitfin
Xenotoca eiseni complex
Semi aggressive
Moderate care
120 L minimum aquarium
5–8 cm adult size
Midwater
Minimum group: 6
About this species
General notes for hobby use.
Redtail Splitfin aquarium complex. The familiar old X. eiseni trade identity now spans three recognised species; use this profile for unidentified aquarium stock and a species-level profile only where provenance/diagnosis is known.
Water parameters
Suggested general range for long-term care.
Temperature
18–25 °C
pH
7–8.2
GH
8–25 dGH
KH
5–18 dKH
Flow preference
Moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 6
Tank zone
Midwater
Territory level
Moderate
Predation risk
Fry
Bioload factor
0.9
Active goodeid livebearer. Redtail splitfins can be assertive and may nip fins; keep a proper group with robust tankmates and plenty of swimming room.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
Yes / caution
Plant safe
Caution
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
4–7 years
Diet type
Omnivore
Minimum aquarium volume
120 L
Minimum footprint
90 × 40 cm
Alternative names
Redtail Splitfin, Red-tailed Goodeid, Xenotoca eiseni, Xenotoca doadrioi, Xenotoca lyonsi, Xenotoca eiseni complex
Native range
West-central Mexico; exact distribution depends on whether the fish is X. eiseni, X. doadrioi or X. lyonsi.
Natural habitat
Streams, springs, ponds and river margins in west-central Mexico; generally mineral-rich water with seasonal temperature variation.
Diet & feeding
Algae/aufwuchs, detritus, small invertebrates and prepared foods; use a vegetable-rich staple with varied frozen/live foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Males are smaller and more intensely coloured with a modified anterior anal-fin structure; females are larger and fuller-bodied.
Breeding
Matrotrophic goodeid livebearer. Females produce relatively small broods of large young nourished during gestation via trophotaeniae.