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FishmediumFreshwater

Swordtail Characin

Corynopoma riisei

📍 South America (Trinidad and Venezuela)

The Swordtail Characin is a fascinating and unusual livebearer-like characin from Trinidad and Venezuela, notable for the male's elongated gill cover appendage that mimics a small crustacean to lure females. Females can store sperm for months and produce multiple broods from a single mating. They are a rewarding species for intermediate hobbyists who appreciate unique reproductive strategies and subtle beauty.

Size2.5"
Min Tank20g
School6+
peaceful
Zonemiddle

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Care Guide

Diet

Swordtail Characins are carnivores that thrive on small live and frozen foods such as daphnia, baby brine shrimp, micro worms, and bloodworms. They will also accept high-quality micro pellets and small flake foods, though live foods are strongly recommended to maintain conditioning and encourage breeding. Feed small amounts two to three times daily, ensuring all food is consumed within a few minutes.

Behavior

This species is generally peaceful and active, spending most of its time in the middle water column among plants and open swimming areas. Males display their distinctive elongated gill appendage to attract females and may occasionally spar with one another, but rarely cause injury. They do best in groups of six or more, which reduces stress and encourages natural schooling and courtship behaviors.

Breeding

Breeding is highly unique among characins — females are internally fertilized and can store sperm for extended periods, giving birth to live, free-swimming fry without needing a male present for each brood. Provide dense vegetation such as java moss or fine-leaved plants for fry to hide in, as adults may consume offspring. Fry are relatively large at birth and can accept baby brine shrimp and micro worms immediately.

Common Diseases

Ich (White Spot Disease)

Symptoms

Small white salt-like spots on body and fins, flashing against surfaces, lethargy

Treatment

Raise temperature gradually to 28-29 C (82-84 F) and treat with ich medication such as malachite green or copper-based treatments; ensure good water quality

Velvet (Oodinium)

Symptoms

Fine gold or rust-colored dust on skin, rapid gill movement, clamped fins, lethargy

Treatment

Dim tank lighting, treat with copper-based medication or acriflavine; perform water changes and quarantine affected fish

Bacterial Fin Rot

Symptoms

Frayed, discolored, or receding fins; white or red edges on fin tissue

Treatment

Improve water quality with frequent water changes; treat with antibacterial medication such as kanamycin or erythromycin

Internal Parasites

Symptoms

Wasting despite good appetite, stringy white feces, bloating, lethargy

Treatment

Treat with antiparasitic medication such as metronidazole or fenbendazole added to food or water; quarantine affected individuals

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Quick Facts

diet
Carnivore – prefers small live and frozen foods such as daphnia, brine shrimp, and micro worms; will accept quality flake and micro pellets
lifespan
3-5 years
max size
6.5 cm (2.5 in)
tank size
20 gallons minimum
temperament
peaceful

Water it likes

ph
6.5-7.5
ammonia
0 ppm
nitrate
<20 ppm
hardness
4-15 dGH
temperature
72–81°F (22–27°C)

Stats

Community tips0
Kept by0 hobbyists