Two-banded killifish

Geographic Origin and Biotope: Originating from streams and coastal pools in south-eastern Nigeria and south-western Cameroon. Inhabits the marginal and shaded areas of freshwater rivulets, rich in submerged roots and leaf litter.

Taxonomy and Morphology: Two-striped Killifish (Aphyosemion bivittatum / ex-Chromaphyosemion bivittatum). The name "bivittatum" comes from the two longitudinal black stripes on the flanks, visible especially in females or stressed males.

Social Behavior: Typically shy, prefers the protection of a thick plant tangle. Males engage in extensive "displays", fully spreading their wide fins to intimidate rivals or charm females, rarely causing serious injuries.

Coloration and Sexual Dimorphism: The male is a kaleidoscope of colors: golden-reddish body, blue/metallic green iridescence and wide veiled dorsal and anal fins towering on the back ("Sailfin"). Females are brownish and show the two horizontal lines markedly.

Aquarium Setup: 60 cm (24 inches) aquarium for one or two pairs. Very dark water (Blackwater) filtered with peat and woods releasing tannins. Abundance of Anubias, Java ferns and mosses needed to create dens and spawning sites. Dim lighting.

Diet and Feeding: Micro-predator. Does not survive well on flake food alone. Requires brine shrimp nauplii, daphnia, white worms (Grindal worms) and frozen bloodworms. Live food immediately triggers the hunting instinct and reproductive colors.

Water Quality: Stable water parameters are fundamental: tolerates modest chemical variations, but a rapid drop in pH or thermal shocks can be lethal. Excellent biological filtration without direct currents is vital.

Compatibility and Tankmates: Fish to be kept strictly in a monospecific tank or, at most, in an ultra-peaceful nano-community aquarium (Small Rasboras, Pygmy Corydoras). Do not mix with other Killifish of the Chromaphyosemion genus to avoid fatal hybridizations.

Aquarium Reproduction: Non-annual Killifish. Lays a few adhesive eggs a day in mosses (or on acrylic yarn mops). Eggs take about 14-18 days to hatch lying in water (water incubation). It is prudent to isolate the eggs from the greedy parents.

Risks and Diseases: High susceptibility to bacteriosis of the long and delicate fins if tank hygiene is poor. Unstoppable tendency to jump: a perfect cover without the slightest crack is the only way not to find them dried out on the floor.