Killifish / Rivulinae / Black-Tailed Rivulus

Black-Tailed Rivulus, Blue-Stripe Rivulus
Rivulus xiphidius

Synonyms: None
Physical description: An elongated species with a rounded caudal fin.   The back of males is reddish-brown as are the upper flanks.  An iridescent blue band extends from the pectoral fin to the caudal penuncle.   The band become black from the pectoral fin to the snout, and from the caudal penuncle to the end of the caudal fin.   The belly is sliver-white.  A fine turquoise stripe runs above the blue and black band.   The fins are reddish-brown, except for the blue base of the anal fin, and the continuation of the black and turquoise stripes on the caudal fin.
Size/Length: To 1.5" (4 cm)
Similar species: None
Habitat: South America; inhabits small streams in coastal Surinam and French Guyana.
S: all
Aquarium: A tank measuring 16" (40 cm) with a capacity of 5 gallons (19 L) is adequate.   Follow recommendations for R. agilae
Water chemistry: 5.5-6.7 (6.2), 2-6 dH (4), 73-77°F (23-25°C)
Social behavior: A peaceful species that is more seclusive than R. agilae.   Males should be given plenty of space in order to set up territories.  This species is perhaps best kept in a tank of its own.  
Suggested companions: Small schooling characins, Corydoras catfish.
FOOD: Live; insects, insect larvae, crustaceans, Tubifex; flakes
SEX: Males are larger and more colorful.
Breeding techniques: Use a small tank furnished with Java Moss and a substrate of peat.   Keep one male with two or three females.   Use water with a pH from 5.5-6.0, a dH from 2-4 dH, and a temperature from 75-79°F (24-26°C).   The fish spawn continuously for ten to 14 days.  Remove the substrates from the tank and place store them for three weeks.   Soft water can be added, and the fry should be raised on Artemia nauplii.
Breeding potential: 8.  Breeding is difficult.
Remarks: The two Rivulus species in this book are exceptions from other Rivulus species in their sensitivity.   Several Rivulus species are considered hardy Killifish.

By Rhett Butler   Mongabay.com