© Mattia Nocciola / CC BY-SA 4.0Redtail Splitfin
The Redtail Splitfin is a livebearing tropical fish from Mexico's Goodeidae family, prized for the orange-to-red blush at the base of its tail fin that adds a striking splash of color to any tank. As a livebearer, it gives birth to live fry rather than laying eggs, making its breeding behavior easy to observe. Hardy and tolerant of changing conditions, it's considered a good choice for beginners — though its somewhat feisty temperament means it can nip at other fish's fins and eyes, so keeping it as the sole species is generally recommended. Reaching a compact 6–7 cm as an adult, it brings lively movement and vivid color to the aquarium.
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Apply as a breederRedtail Splitfin key facts
- Care level
- Beginner-friendly
- Lifespan
- 3-5 years
- Size
- 6-7cm
- Temperature
- 15〜30℃
- Diet
- Prepared foods, frozen foods, live foods
- Tank
- Seriously Fish suggests a 60 x 30cm base of about 54 litres. Dense planting over a dark substrate shows the colour to best effect.
- Water Temperature & Quality
- Seriously Fish gives 15-30C, pH 6.0-8.0 and 10-20dGH. FishBase records a wide 15-32C in the wild, reflecting its adaptability.
- Tank Mates
- Seriously Fish calls its behaviour unpredictable and recommends a species tank. It may nip fins or kill other species, and combinations with catfish such as corydoras should be avoided.
- Diet & Feeding
- Unfussy, it accepts dried, frozen and live foods alike.
- Breeding & Spawning
- Breeding is easy. Females cannot store sperm, so each brood requires a fresh mating. Gestation is seven to eight weeks and produces five to fifty young. Newborns may carry what looks like an umbilical cord; this is normal and disappears in two or three days.
- Health & Notes
- Seriously Fish describes it as incredibly hardy and adaptable. IUCN status is Endangered. Stock labelled San Marcos may belong to the separate species Xenotoca doadrioi, so check the locality given.
About Redtail Splitfin
An introduction to the Redtail Splitfin, a hardy livebearing tropical fish from Mexico's Goodeidae family known for its red-tinted tail fin — a beginner-friendly species best kept alone.
7 things to know before welcoming a Redtail Splitfin
1Best Kept Alone
Its somewhat feisty temperament means it may nip at other fish's fins and eyes, so keeping it as a single species is safer than a mixed tank. Hierarchies can form even among its own kind, so provide plenty of hiding spots.
2A Livebearing Species
This fish gives birth to live fry instead of laying eggs. Keeping males and females together often leads to breeding, and you may notice fry in the tank before long.
3Hardy and Beginner-Friendly
It tolerates changing water conditions well and is considered suitable for beginners. Even so, avoid sudden shifts in water quality and keep up with regular water changes.
4Watch the Tail Coloration
The orange-to-red blush at the base of the tail fin is its signature feature. The intensity can vary with water conditions, diet, and the individual fish's condition.
5A Compact Adult Size
Adults reach about 6–7 cm, making them manageable even without a large tank.
6A Mexican Goodeidae Species
It belongs to the Goodeidae (goodeid) family, a lineage that's uncommon in Japan. Knowing its distinct traits helps you understand its care needs.
7Prepare the Tank Before Arrival
Since single-species housing is recommended, set up the layout and hiding spots with that in mind so the fish settles in smoothly after coming home.
Frequently asked questions about Redtail Splitfin
- Q.Can it be kept with other fish?
- A.The Redtail Splitfin has a somewhat feisty temperament and may nip at other fish's fins and eyes, so keeping it as the only species is generally recommended. If you do try mixed tanks, watch size differences and compatibility closely.
- Q.Is it suitable for beginners?
- A.Yes, it's considered beginner-friendly thanks to its hardiness and tolerance for changing water conditions. Basic water quality management is usually enough to keep it thriving.
- Q.Is it easy to breed?
- A.As a livebearer, it gives birth to live fry rather than laying eggs. Keeping males and females together often leads to natural breeding.
- Q.How big do adults get?
- A.Adults reach about 6–7 cm, making it a relatively compact tropical fish.
- Q.Is it subject to any special regulations?
- A.The Redtail Splitfin is not subject to CITES.
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Learn more about Redtail Splitfin in the encyclopedia
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Care difficulty, lifespan, size and diet — all basics covered.
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